Gurpreet has 2,500 sweets to pack in boxes of 13, with no sweet left over. What is the least number of extra sweets she must buy?

4Correct answerYour answer7Correct answerYour answer9Correct answerYour answer13Correct answerYour answer

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CorrectNot quiteAnswer C

Correct answer: C

$13 \times 192 = 2{,}496$ , so 2,500 leaves a remainder of 4 when divided by 13.
To reach the next multiple, $13 \times 193 = 2{,}509$ , she needs $13 - 4 = 9$ more.

Worth noting

4 is the remainder — the number to REMOVE, not to add. The number to add is divisor − remainder.

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