What will be the remainder when 97531 is divided by 9?
7
7 is correct.
This works because 10 leaves remainder 1 on division by 9, so every power of 10 also leaves remainder 1.
A number leaves the same remainder on division by 9 as the sum of its digits.
Sum of digits \(=9+7+5+3+1=25\).
\(25=2\times 9+7\), so the remainder is 7.
Which of the following is divisible by 15?
What smallest number should be added to 16809 so that the sum is completely divisible by 41?