Video: Finding the Product of Two Numbers by Subtracting from a Given Related Product

Scarlett knows the answer to 9 × 3. Tell her what to subtract from this to find the answer to 7 × 3. What is 7 × 3?

01:19

Video Transcript

Scarlett knows the answer to nine multiplied by three. Nine multiplied by three equals 27. Tell her what to subtract from this to find the answer to seven multiplied by three. What is seven multiplied by three?

Nine multiplied by three is the same as saying nine groups of three. We’re already told in the problem the number fact that nine multiplied by three equals 27. Seven groups of three is two groups of three less than nine groups of three. So we can cross out two groups of three to show this.

This is six less. So Scarlett needs to subtract six from 27 to find the answer. 27 subtract six equals 21.

So we also know that seven multiplied by three equals 21.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.