Chen uses these digit cards: five, six, and nine. She makes a two-digit number and a one-digit number. She multiplies them together. Her answer is a multiple of 10. What could Chen’s multiplication be?
So we know that Chen has three cards: a five, a six, and a nine. She uses them to make a two-digit number and a one-digit number. Then she multiplies them together. Her answer is a multiple of 10. We need to work out what her multiplication could be. In other words, we need to write the five, the six, and the nine into the correct place on the blank digit cards.
So to answer the question, we need to work out which two-digit number multiplied by a one-digit number gives us an answer which is a multiple of 10. Five times six or six times five gives us 30. 30 is a multiple of 10. Five times nine or nine times five is 45. Six times nine or nine times six is 54. So the only two possible combinations of numbers that we can multiply together are five and six or six and five. So we can write these digits into the blank cards. So we’ve used the five and the six digit, which just leaves the nine to write into the last blank card.
So Chen’s multiplication could be 96 multiplied by five or 95 multiplied by six, because five and six are the only two numbers we can multiply together to give us a multiple of 10. So we have two possible answers to this question: 96 multiplied by five or 95 multiplied by six.