Quick Prime or Composite Number Test: The last digit of **345** is 5, so it can be evenly divided by 5. Therefore, 345 is a composite number.

Print the puzzles or type the factors on this excel file: 10 Factors 2015-01-05

- 345 is a composite number.
- Prime factorization: 345 = 3 x 5 x 23
- 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 x 2 x 2 = 8. Therefore 345 has exactly 8 factors.
- Factors of 345: 1, 3, 5, 15, 23, 69, 115, 345
- Factor pairs: 345 = 1 x 345, 3 x 115, 5 x 69, or 15 x 23
- 345 has no square factors that allow its square root to be simplified. √345 ≈ 18.574

**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 (1st column) and factor row (top 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 factor column and the factor row one cell at a time as you go.