Multiply a 3-digit by a 1-digit number with one or two regroups

I can multiply a 3-digit by a 1-digit number using expanded and short multiplication (one or two regroups).

New

Year 5

I can multiply a 3-digit by a 1-digit number using expanded and short multiplication (one or two regroups).

Slide deck

If the product of the ones digits is greater than 10 then you regroup ten ones into one ten.
If the product of the 1-digit number and the tens digit is greater than 100 then you regroup ten 10s into one 100
If the product of the 1-digit number and the 100s digit is greater than 1,000 then you regroup ten 100s into one 1,000

Children may misalign digits when arranging into the short multiplication layout.

Children should use unitising language to help them understand and apply this to formal written methods.

Regroup - The process of unitising and exchanging between place values is known as regrouping.
Expanded multiplication - A way of recording the steps of a calculation focusing on partitioning one or more factors and showing partial products.
Short multiplication - A way of recording using columns to set out and calculate a multiplication.

Draw attention to regrouping. ‘If there are ten or more tens, we must regroup the tens into hundreds and tens.’

Teacher tip

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