Question

put a check by all the prime numbers.
3
7
9
15
26
28
none of the above

Explanation:

Step1: Recall prime number definition

A prime number is a number greater than 1 that has no positive divisors other than 1 and itself.

Step2: Check each number

• For 3: Divisors are 1 and 3. So prime.
• For 7: Divisors are 1 and 7. So prime.
• For 9: Divisors are 1, 3, 9. Not prime (3×3=9).
• For 15: Divisors are 1, 3, 5, 15. Not prime (3×5=15).
• For 26: Divisors are 1, 2, 13, 26. Not prime (2×13=26).
• For 28: Divisors are 1, 2, 4, 7, 14, 28. Not prime (2×14=28, 4×7=28).

Answer:

The prime numbers are 3 and 7, so the checkboxes next to 3 and 7 should be marked. (In the table, the first two checkboxes corresponding to 3 and 7)