The process of unitising and exchanging between place values is known as regrouping.

Expanded multiplication is a way of recording a calculation focusing on partitioning one or more factors and showing partial products.

Multiply a 2-digit number by a 1-digit number using expanded multiplication (regrouping 1s to 10s)

Maths

In this unit pupils will multiply a 2-digit number by a single-digit number using partitioning and representations using expanded multiplication and using short multiplication. In the future unit pupils will multiply a 3-digit number by a single-digit number using expanded and short multiplication.

In the prior unit pupils explained the relationship between multiplying and dividing a number by 10 and multiples of 10. In this unit pupils will multiply a 2-digit number by a single-digit number using partitioning and representations using expanded multiplication and using short multiplication.

Multiplication by partitioning leading to short multiplication (2 by 1-digit)

Look at the image. The arrows are pointing to __________.

Select the correct expanded method shown by this representation.

Sofia believes that you always have a 1-digit partial product when multiplying a 2-digit by a 1-digit number. What do you think?

Which multiplication will need regrouping in the ones column only?

Using Lucas’s grid model, fill in the gap for the expanded multiplication.

Use expanded multiplication to calculate: 3 × 19

Look at this equation. The numbers highlighted in purple are known as {{ }}.

Select the correct representation for this multiplication.

The multiplication is: 73 × 2 Which short multiplication shows this correctly? 

Which representation will require regrouping?

Match the representations A, B and C to the correct multiplication equation.

This lesson will soon be taken down.

Multiply a 2-digit number by a 1-digit number using expanded multiplication (regrouping 1s to 10s)

Lesson outcome