If you know the greatest common factor of 15 and 20, then you can begin to solve this puzzle. Since this is a level 3 puzzle, look at the clues starting at the top of the puzzle and work your way down, writing in the factors as you go. You can do this!

Print the puzzles or type the solution in this excel file: 10-factors-1242-1250

Now I’ll share some facts about the number 1245:

• 1245 is a composite number.
• Prime factorization: 1245 = 3 × 5 × 83
• The exponents in the prime factorization are 1, 1, and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1)(1 + 1) = 2 × 2 × 2 = 8. Therefore 1245 has exactly 8 factors.
• Factors of 1245: 1, 3, 5, 15, 83, 249, 415, 1245
• Factor pairs: 1245 = 1 × 1245, 3 × 415, 5 × 249, or 15 × 83
• 1245 has no square factors that allow its square root to be simplified. √1245 ≈ 35.28456

1245 is also the hypotenuse of a Pythagorean triple:
747-996-1245 which is (3-4-5) times 249