Question Video: Multiplying Two-Digit Numbers by One-Digit Numbers to Complete a Multiplication Sentence Mathematics • 4th Grade

Find the number that can replace the question mark in the following: 56 × 3 = 16?


Video Transcript

Find the number that can replace the question mark in the following: 56 multiplied by three.

In this question, we’re shown the calculation 56 multiplied by three. But one of the digits is missing. When we’re multiplying a two-digit number by a one-digit number using the standard written method, we always start by multiplying the ones first. The number 56 has six ones, and we have to multiply them by three. We know that six times three equals 18. And we know that the number 18 has one 10 and eight ones. So we can write the ones digit in the ones column. This is the missing digit. We know that 18 has eight ones and one 10, so we would need to regroup 10 of our ones and exchange them for one 10. We’ve written the 10 in the tens column.

Although the rest of the calculation has been done for us, we can work through it to make sure the answer’s correct. Our next step is to multiply our five 10s by three. Five 10s multiplied by three gives us 15 10s. But we need to add the one that we regrouped. 15 10s and one more gives us 16 10s. We can write the six in the tens column and the one in the hundreds column. So 56 multiplied by three equals 168. The missing digit which replaces the question mark is eight. All we had to do to find the missing digit was multiply the ones. The missing digit is eight.

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