Question: Which of the following is a correct statement about divisibility by 7?

Options:

1. A number must end in 7
2. Double the last digit and subtract it from the rest
3. The sum of the digits must be divisible by 7
4. A number must be a multiple of 14

Correct Answer: Double the last digit and subtract it from the rest

Solution:

To check for divisibility by 7, you can double the last digit and subtract it from the rest of the number.