Author: Nick Snels
Publisher: PuzzleBooks.net
ISBN: 1508566933
Category : Games & Activities
Languages : en
Pages : 311
Book Description
When you buy this book you get an electronic version (PDF file) of the interior of this book. Kakuro is a fun and addicting logic puzzle game. This book is ideal if you love to play Kakuro no matter their size. This book is ideal for beginners to learn how to solve different sizes of Kakuro. You get the perfect mix of different sizes of Kakuro to keep you entertained for weeks. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 large print puzzle per page, with lots of white space for scribbling. Kakuro Mixed Grids Large Print is a collection of 270 puzzles: 54 easy Kakuro 13x13 puzzles 54 easy Kakuro 14x14 puzzles 54 easy Kakuro 15x15 puzzles 54 easy Kakuro 16x16 puzzles 54 extra logic puzzles The goal of Kakuro is to insert numbers into the white cells. Possible numbers are always 1 to 9. The sum of each horizontal block must equal the clue on its left. The sum of each vertical block must equal the clue above it. You can only use a number once in each horizontal or vertical block. I guarantee that every logic puzzle in this Kakuro puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other English PuzzleBooks.net books. Kakuro is also known as Cross Sums, Kakro, Kakkuro, Cross Addition. Quite often Kakuro is misspelled as Kakura.
Kakuro Mixed Grids Large Print - Volume 5 - 270 Logic Puzzles
Author: Nick Snels
Publisher: PuzzleBooks.net
ISBN: 1508566933
Category : Games & Activities
Languages : en
Pages : 311
Book Description
When you buy this book you get an electronic version (PDF file) of the interior of this book. Kakuro is a fun and addicting logic puzzle game. This book is ideal if you love to play Kakuro no matter their size. This book is ideal for beginners to learn how to solve different sizes of Kakuro. You get the perfect mix of different sizes of Kakuro to keep you entertained for weeks. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 large print puzzle per page, with lots of white space for scribbling. Kakuro Mixed Grids Large Print is a collection of 270 puzzles: 54 easy Kakuro 13x13 puzzles 54 easy Kakuro 14x14 puzzles 54 easy Kakuro 15x15 puzzles 54 easy Kakuro 16x16 puzzles 54 extra logic puzzles The goal of Kakuro is to insert numbers into the white cells. Possible numbers are always 1 to 9. The sum of each horizontal block must equal the clue on its left. The sum of each vertical block must equal the clue above it. You can only use a number once in each horizontal or vertical block. I guarantee that every logic puzzle in this Kakuro puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other English PuzzleBooks.net books. Kakuro is also known as Cross Sums, Kakro, Kakkuro, Cross Addition. Quite often Kakuro is misspelled as Kakura.
Publisher: PuzzleBooks.net
ISBN: 1508566933
Category : Games & Activities
Languages : en
Pages : 311
Book Description
When you buy this book you get an electronic version (PDF file) of the interior of this book. Kakuro is a fun and addicting logic puzzle game. This book is ideal if you love to play Kakuro no matter their size. This book is ideal for beginners to learn how to solve different sizes of Kakuro. You get the perfect mix of different sizes of Kakuro to keep you entertained for weeks. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 large print puzzle per page, with lots of white space for scribbling. Kakuro Mixed Grids Large Print is a collection of 270 puzzles: 54 easy Kakuro 13x13 puzzles 54 easy Kakuro 14x14 puzzles 54 easy Kakuro 15x15 puzzles 54 easy Kakuro 16x16 puzzles 54 extra logic puzzles The goal of Kakuro is to insert numbers into the white cells. Possible numbers are always 1 to 9. The sum of each horizontal block must equal the clue on its left. The sum of each vertical block must equal the clue above it. You can only use a number once in each horizontal or vertical block. I guarantee that every logic puzzle in this Kakuro puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other English PuzzleBooks.net books. Kakuro is also known as Cross Sums, Kakro, Kakkuro, Cross Addition. Quite often Kakuro is misspelled as Kakura.
Killer Sudoku - 200 Hard to Master Puzzles 9x9
Author: Oliver Quincy
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985126657
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985126657
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Kakuro
Author: Johnny Wong
Publisher: Gramercy
ISBN: 9780517229422
Category : Kakuro
Languages : en
Pages : 0
Book Description
Called the next big thing in Japanese number puzzles, Kakuro features Sudoku-like puzzles with a twist. This collection features 200 new puzzles.
Publisher: Gramercy
ISBN: 9780517229422
Category : Kakuro
Languages : en
Pages : 0
Book Description
Called the next big thing in Japanese number puzzles, Kakuro features Sudoku-like puzzles with a twist. This collection features 200 new puzzles.
Samurai Sudoku - Medium - Volume 3 - 159 Puzzles
Author: Nick Snels
Publisher: PuzzleBooks.net
ISBN: 1502788144
Category : Games & Activities
Languages : en
Pages : 180
Book Description
When you buy this book you get an electronic version (PDF file) of the interior of this book. Samurai Sudoku is Sudoku on steroids. It combines 5 Sudoku's into one large fun and addicting logic puzzle game that will give you hours of puzzle pleasure. This book is ideal for you if you already know how to solve Samurai Sudoku puzzles but you find our hard or extreme Samurai Sudoku puzzles too difficult. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 Samurai Sudoku puzzle per page, with lots of white space for scribbling. Samurai Sudoku consists of five 9x9 grids, one in the center and the other 4 overlapping each corner grid of the central one. For each 9x9 grid the goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1-9 exactly once. Samurai Sudoku - Medium is a collection of 159 puzzles: 120 medium Samurai Sudoku puzzles 39 extra logic puzzles I guarantee that every logic puzzle in this Samurai Sudoku puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other PuzzleBooks.net books. Samurai Sudoku is also known as Gattai-5.
Publisher: PuzzleBooks.net
ISBN: 1502788144
Category : Games & Activities
Languages : en
Pages : 180
Book Description
When you buy this book you get an electronic version (PDF file) of the interior of this book. Samurai Sudoku is Sudoku on steroids. It combines 5 Sudoku's into one large fun and addicting logic puzzle game that will give you hours of puzzle pleasure. This book is ideal for you if you already know how to solve Samurai Sudoku puzzles but you find our hard or extreme Samurai Sudoku puzzles too difficult. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 Samurai Sudoku puzzle per page, with lots of white space for scribbling. Samurai Sudoku consists of five 9x9 grids, one in the center and the other 4 overlapping each corner grid of the central one. For each 9x9 grid the goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1-9 exactly once. Samurai Sudoku - Medium is a collection of 159 puzzles: 120 medium Samurai Sudoku puzzles 39 extra logic puzzles I guarantee that every logic puzzle in this Samurai Sudoku puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other PuzzleBooks.net books. Samurai Sudoku is also known as Gattai-5.
Killer Sudoku - 200 Hard Puzzles 9x9
Author: Oliver Quincy
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985097056
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985097056
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Killer Sudoku - 200 Hard to Master Puzzles 9x9
Author: Michael Brown
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727761863
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727761863
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Killer Sudoku - 200 Hard Puzzles 9x9
Author: Michael Brown
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727732542
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727732542
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Killer Sudoku - 200 Easy to Master Puzzles 9x9
Author: Oliver Quincy
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985015388
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781985015388
Category :
Languages : en
Pages : 138
Book Description
About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. * Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. * Every cell is a part of a cage, indicated by dotted line. * Make sure the cells can be added up to the sum of its cage. * Numbers cannot repeat within cage. * Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Killer Sudoku - 200 Easy to Master Puzzles 9x9
Author: Michael Brown
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727733822
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher: Createspace Independent Publishing Platform
ISBN: 9781727733822
Category :
Languages : en
Pages : 52
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Killer Sudoku - 200 Easy to Normal Puzzles 9x9
Author: Michael Brown
Publisher:
ISBN: 9781651288481
Category :
Languages : en
Pages : 54
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.
Publisher:
ISBN: 9781651288481
Category :
Languages : en
Pages : 54
Book Description
Killer Sudoku (also known as "Sums Sudoku", "Sums Number Place", "Samunamupure", "Kikagaku Nampure") is a mathematical and logical puzzle. About Book This book introduces you to the amazing world of Killer Sudoku puzzles. It will help you understand the rules of this puzzle. This book is perfect for players of all skill levels and ages. You will find 200 exciting puzzles, both for beginners and for professionals. HOW TO PLAY Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x3 region with the numbers 1-9 once. Fill all rows, columns and 3x3 region with numbers exactly like in regular sudoku. Every cell is a part of a cage, indicated by dotted line. Make sure the cells can be added up to the sum of its cage. Numbers cannot repeat within cage. Numbers cannot repeat within a single row, column or 3x3 region. As Killer Sudoku belongs to the same class of puzzles as Sudoku the puzzle can demonstrate a wide spectrum of relative difficulty. The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution. Puzzles almost like Calcudoku, but unlike number cannot appear more than once in a block.