New
New
Year 5

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
New
Year 5

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).

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Lesson details

Key learning points

  1. If the product of the ones digits is greater than 10 then you regroup ten ones into one ten.
  2. If the product of the 1-digit number and the tens digit is greater than 100 then you regroup ten 10s into one 100
  3. 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

Keywords

  • 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.

Common misconception

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.

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

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
What’s the next number in the sequence: 11, 22, 33, ___
34
Correct answer: 44
54
64
Q2.
Look at the short multiplication. ___ tens have been regrouped.
An image in a quiz
Correct Answer: 2, two, Two
Q3.
Look at the expanded multiplication. tens have been regrouped.
An image in a quiz
Correct Answer: 3, three, Three
Q4.
Select the representation which shows: 42 × 3
Pic 1
Pic 2
Correct answer: Pic 3
Pic 4
Q5.
Use a formal or informal method to solve this word problem: If all these boxes are the same height, how tall is the stack of boxes?
An image in a quiz
Correct Answer: 93 cm, 93, ninety three, Ninety-three, Ninety-three cm
Q6.
Find the missing number.
An image in a quiz
Correct Answer: 6, six, Six

6 Questions

Q1.
Which multiple is the odd one out?
5
Correct answer: 7
10
15
20
Q2.
Select the correct expanded arrangement for:
An image in a quiz
Correct answer: Pic 1
Pic 2
Pic 3
Q3.
Which multiplication will need regrouping in the ones column only?
323 × 3
Correct answer: 325 × 3
323 × 2
303 × 3
Q4.
Use expanded multiplication to solve: 422 × 4. Write the product in numeral form.
Correct Answer: 1688
Q5.
Use short multiplication to solve: 406 × 6. Write the product in numeral form.
Correct Answer: 2,436
Q6.
What could the missing number be?
An image in a quiz
Correct Answer: 5, five