New
New
Predicting the size of a product
I can explain how to use the size of one number in a multiplication to predict the size of the product.
Lesson 13 of 15
New
New
- Year 5
Predicting the size of a product
I can explain how to use the size of one number in a multiplication to predict the size of the product.
Lesson details
Key learning points
- If one factor is made ___ times the size and the other factor remains the same, the product will be ___ times the size.
- When a number is multiplied by a value less than one, the product is smaller than the original number.
- When a number is multiplied by a value greater than one, the product is greater than the original number.
Keywords
Product - The product is the result of two or more numbers multiplied together.
Factor - Factors are integers that are multiplied together to get a product.
Common misconception
Children may think that multiplication always makes things larger. Children may scale incorrectly.
When a number is multiplied by a value less than 1, the product is smaller than the original number - multiplication doesn't always make things larger. Compare numbers: if one factor is made ___ times the size, the product will be ___ times the size.
Refer to keyword definition - a factor is an integer so decimal fractions cannot be considered factors. Provide children with scaffolded support it they are not confident with their times-tables.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), 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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Prior knowledge starter quiz
6 Questions
Q1.Match the number to its written representation.
Match the number to its written representation.
Q2.Complete the equations by matching the expression with its missing part.
Complete the equations by matching the expression with its missing part.
Q3.Match the expression to its product.
Match the expression to its product.
Q4.Match the expression to its product.
Match the expression to its product.
Q5.Match the expression to its product.
Match the expression to its product.
Q6.Which of the following would make this calculation correct?
43 > 8 × ___
Which of the following would make this calculation correct?
43 > 8 × ___
6
7
8
Assessment exit quiz
6 Questions
Q1.Use the fact that 9 × 8 = 72, to match the expressions to their product.
Use the fact that 9 × 8 = 72, to match the expressions to their product.
Q2.If 6 × 72 = 432, what does 6 × 0.72 equal?
If 6 × 72 = 432, what does 6 × 0.72 equal?
4,320
432
43.2
0.432
Q3.True or False? 13 × 0.9 will have a product that is smaller than 13
True or False? 13 × 0.9 will have a product that is smaller than 13
False
Q4.Match the expression with its missing symbol < > or =
Match the expression with its missing symbol < > or =
Q5.Which of the following would make this calculation correct? 3.4 > 0.9 × ___
Which of the following would make this calculation correct? 3.4 > 0.9 × ___
4
5
6
Q6.Which of the following will have a product greater than the original number being multiplied?
Which of the following will have a product greater than the original number being multiplied?
6 × 0.2
6 × 1
6 × 0
