Question

Greta’s solution to 961x4 is 3,644. Is she correct? Use what you know about three-digit by one-digit multiplication to explain your answer.

Answer 1

Firstly, 961 x 4 = 3844

This means that Greta's solution is incorrect.

For three-digit by one-digit multiplication, the place value of the 3 digits are hundred, tens and one. Thus, for 961,

9 has a place value of hundred

6 has a place value of ten

1 has a place value of one

When applying the three-digit by one-digit multiplication, we would muliply each digit in the different place value positions by 4. Starting from the ones, We have

4 x 1 = 4

For the digit in the tens position, we have

4 x 6 = 24

We would write down 4 and hold 2(because 24 is greater than or equal to 10 and we are working with base 10 numbers). Next, multiply 4 by the digit in the hundreds position. we have

4 x 9 = 36

We would add the 2. It becomes 38

By combining the results in the 3 stages, we have 3844