How many different factors does 72 have, including 1 and 72?
Answer and explanation
Correct answer: B. 12
- Step 1: List in pairs: 1 × 72, 2 × 36, 3 × 24, 4 × 18, 6 × 12 and 8 × 9. Step 2. Each pair gives two different factors, so 6 × 2 = 12 factors. Answer: 12. Why not the others: 6: This is the number of factor pairs, not the number of factors. 7: This counts only the factors up to 9. 18: This is one of the factors of 72, not the number of them.
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