A Multiplication Based Logic Puzzle

Posts tagged ‘irrational number’

199 and My List of Multiplication Rhymes

199 is a prime number.
Factor pairs: 199 = 1 x 199
Factors of 199: 1, 199
Prime factorization: none

How do we know that 199 is a prime number? The square root of 199 is an irrational number approximately equal to 14.11. If 199 were not a prime number, then it would be divisible by at least one prime number less than or equal to 14.11. Since 199 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 199 is a prime number.

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I recently wrote a post that asked “Are Multiplication Rhymes Able to Help Kids Learn the Multiplication Table?” No list is perfect, but here is a list of rhymes that I’ve put together.

Multiplication Rhymes

 

Most of the rhymes have rhyming clues to help students remember both numbers being multiplied as well as their product. I wrote the rhymes that are highlighted in yellow. Those highlighted in peach, purple, or blue are from other sources, but I did alter the rhymes for 24, 28, and 81. A black and white pdf of the rhymes is also available here.

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197 and Level 5

197 is a prime number.
Factor pairs: 197 = 1 x 197
Factors of 197: 1, 197
Prime factorization: none

How do we know that 197 is a prime number? The square root of 197 is an irrational number approximately equal to 14.04. If 197 were not a prime number, then it would be divisible by at least one prime number less than or equal to 14.04. Since 197 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 197 is a prime number.

2014-31 Level 5

Excel file of puzzles and previous week’s factor solutions: 10 Factors 2014-08-04

2014-31 Level 5 Logic

193 and Level 2

193 is a prime number.
Factor pairs: 193 = 1 x 193
Factors of 193: 1, 193
Prime factorization: none

How do we know that 193 is a prime number? The square root of 193 is an irrational number approximately equal to 13.89. If 193 were not a prime number, then it would be divisible by at least one prime number less than or equal to 13.89. Since 193 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 193 is a prime number.

2014-31 Level 2

Excel file of puzzles and previous week’s factor solutions: 10 Factors 2014-08-04

2014-31 Level 2 Factors

191 and Level 6

191 is a prime number.
Factor pairs: 191 = 1 x 191
Factors of 191: 1, 191
Prime factorization: none
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There are 22 prime numbers between 100 and 200.
The first four prime numbers greater than 100 are 101, 103, 107, and 109.
The last four prime numbers less than 200 are 191, 193, 197, and 199.

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How do we know that 191 is a prime number? The square root of 191 is an irrational number approximately equal to 13.82. If 191 were not a prime number, then it would be divisible by at least one prime number less than or equal to 13.82. Since 191 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 191 is a prime number.

2014-30 Level 6

Excel file of puzzles and previous week’s factor solutions: 12 Factors 2014-07-28

2014-30 Level 6 Logic

2014-30 Level 6 Problems

 

181 and Level 2

181 is a prime number.
Factor pairs: 181 = 1 x 181
Factors of 181: 1, 181
Prime factorization: none

 

How do we know that 181 is a prime number? The square root of 181 is an irrational number approximately equal to 13.45. If 181 were not a prime number, then it would be divisible by at least one prime number less than or equal to 13.45. Since 181 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 181 is a prime number.

2014-29 Level 2

Excel file of puzzles and previous week’s factor solutions: 10 Factors 2014-07-21

2014-29 Level 2 Factors

179 and Level 6

179 is a prime number.
Factor pairs: 179 = 1 x 179
Factors of 179: 1, 179
Prime factorization: none

 

How do we know that 179 is a prime number? The square root of 179 is an irrational number approximately equal to 13.38. If 179 were not a prime number, then it would be divisible by at least one prime number less than or equal to 13.38. Since 179 cannot be divided evenly by 2, 3, 5, 7, 11, or 13, we know that 179 is a prime number.

2014-28 Level 6

Excel file of puzzles and previous week’s factor solutions: 12 Factors 2014-07-14

2014-28 Level 6 Logic

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