A student claims that 157,163 is divisible by 3 since the last digit in the number is 3 . Explain how you would correct the student's thinking. Choose the correct answer below. A. 157,163 is not divisible by 3 because the sum of the digits, 23 , is not divisible by 3 . B. 157,163 is divisible by 3 because the sum of the digits, 24 , is divisible by 3 . C. 157,163 is not divisible by 3 because the first digit in the number is not 3 . D. 157,163 is divisible by 3 because the product of the digits, 630 , is divisible by 3 .

The student's reasoning is flawed because divisibility by 3 is determined by the sum of the digits, not merely the last digit. To check if 157,163 is divisible by 3, we add its digits: 1 + 5 + 7 + 1 + 6 + 3 = 23. Since 23 is not divisible by 3, we can conclude that 157,163 is not divisible by 3. So, the correct answer is A. 157,163 is not divisible by 3 because the sum of the digits, 23, is not divisible by 3. It’s a common misconception that the divisibility rules work similarly for all numbers, but they can be sneaky! Remember, the rule for 3 is all about that digit sum! It’s like a math party, and only those divisible by 3 are allowed to stay!