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.
