A Multiplication Based Logic Puzzle

71 and Level 3

71 is a prime number. 71 = 1 x 71. Its only factors are 1 and 71. Prime factorization: none.

How do we know that 71 is a prime number? The square root of 71 is an irrational number approximately equal to 8.43. If 71 were not a prime number, then it would be divisible by at least one prime number less than or equal to 8.43. Since 71 is not divisible by 2, 3, 5, or 7, it is a prime number.

71 is never a clue in the FIND THE FACTORS puzzles.

2014-12 Level 3

This week’s puzzles for you to solve

A Logical Approach to the Solution: Find the column or row with two clues and find their common factor. Write the corresponding factors in the factor column and factor row.  Because this is a level three puzzle, you have now written a factor at the top of the factor column. Continue to work from the top of the factor column to the bottom, finding factors and filling in the table as you go:

2014-12 Level 3 Factors

A Logical Approach to find the factors: Find the column or row with two clues and find their common factor. Write the corresponding factors in the factor column and factor row.  Because this is a level three puzzle, you have now written a factor at the top of the factor column. Continue to work from the top of the factor column to the bottom, finding factors and filling in the table one row at a time as you go:

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