Predicting the size of a product
Lesson details
Learning outcome
I can explain how to use the size of one number in a multiplication to predict the size of the product.
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.
Teacher tip
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.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the number to its written representation.
0.7
0.9
7
0.07
0.09
Q2.Complete the equations by matching the expression with its missing part.
5
6
8
11
7
Q3.Match the expression to its product.
81
36
1
45
63
Q4.Match the expression to its product.
90
900
9,000
190
1,900
Q5.Match the expression to its product.
0.8
0.08
1.8
0.18
1.08
Q6.Which of the following would make this calculation correct?
43 > 8 × ___
Assessment exit quiz
6 Questions
Q1.Use the fact that 9 × 8 = 72, to match the expressions to their product.
720
7,200
7.2
0
0.72
Q2.If 6 × 72 = 432, what does 6 × 0.72 equal?
Q3.True or False? 13 × 0.9 will have a product that is smaller than 13
Q4.Match the expression with its missing symbol < > or =
<
>
=
Q5.Which of the following would make this calculation correct? 3.4 > 0.9 × ___
Q6.Which of the following will have a product greater than the original number being multiplied?
To help you plan your 5 maths lesson on: Predicting the size of a product, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 5 maths lesson on: Predicting the size of a product, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 2 maths lessons from the Calculating with decimal fractions unit, dive into the full primary maths curriculum, or learn more about lesson planning.