Question

Circle the letter of each of the following numbers that is divisible by 3.

a) 91,821
b) 81
c) 215
d) 588
e) 987

Answer 1

The numbers divisible by 3 are found using the rule that if the sum of the digits of a number is divisible by 3, then the number itself is divisible by 3. After applying this rule, we determine that 91,821, 81, 588, and 987 are divisible by 3.

Step-by-step explanation:

A number is divisible by 3 if the sum of its digits is divisible by 3. Let's apply this rule to find which of the given numbers are divisible by 3:

• a) 91,821: The sum of the digits is 9+1+8+2+1=21, which is divisible by 3. Therefore, 91,821 is divisible by 3.
• b) 81: The sum of the digits is 8+1=9, which is divisible by 3. Thus, 81 is divisible by 3.
• c) 215: The sum of the digits is 2+1+5=8, which is not divisible by 3. Hence, 215 is not divisible by 3.
• d) 588: The sum of the digits is 5+8+8=21, which is divisible by 3. So, 588 is divisible by 3.
• e) 987: The sum of the digits is 9+8+7=24, which is divisible by 3. Therefore, 987 is divisible by 3.

The numbers that are divisible by 3 are: a) 91,821, b) 81, d) 588, and e) 987.