Starter quiz
- Tick the factors of 20
- 2 ✓
- 3
- 5 ✓
- 15
- 20 ✓
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- The commutative law states that:
- You must start multiplying with the first factor in an equation.
- You can reorder the factors in an equation and the product will remain the same. ✓
- You can reorder the factors in an equation but the product will change.
-
- If a pair of brackets are placed around two factors such as in 2 × (4 × 7) = , this means:
- You should multiply these factors first. ✓
- You should multiply these factors last.
- You do not need to multiply these factors.
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- Match the equation to the factor pairs that would be best used to help solve the calculations.
- 25 × 36 = ___⇔4 and 9 ✓
- 28 × 50 = ___⇔2 and 14 ✓
- 20 × 65 = ___⇔5 and 13 ✓
Find the product of this equation.- '300' ✓
- Find the product of this equation. 50 × 54 = ______
- '2,700' ✓
Exit quiz
- Which factors would be best to associate together to calculate efficiently? 4 × 5 × 7 = ___
- 4 and 5 ✓
- 5 and 7
- 7 and 4
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- Tick the three factor equations that would be equal to this two factor equation. 15 × 20 = ___ × ___ × ___
- 15 × 4 × 5 ✓
- 15 × 3 × 5
- 3 × 5 × 20 ✓
- 15 × 2 × 10 ✓
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- Tick the numbers that could be multiplied by a one digit number and would be equal to a multiple of 10.
- 8 ✓
- 9
- 12 ✓
- 15 ✓
-
Find the product of this equation.- '900' ✓
- Match the 4 factor equations that are equal to the two factor equations.
- 4 × 4 × 3 × 5⇔16 × 15 ✓
- 3 × 6 × 4 × 6⇔18 × 24 ✓
- 2 × 6 × 3 × 7⇔21 × 12 ✓
- 4 × 11 × 3 × 5⇔33 × 20 ✓
- Find the product of this equation. 32 × 15 = ______
- '480' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- By rearranging a calculation it can be made easier to solve mentally
Common misconception
Pupils may struggle to find factors of a number if they do not have automatic recall of their times tables.
Provide children with a multiplication grid to help pupils understand the process of the calculations, however ensure additional support is in place for children to build towards automatic recall of times tables.
Keywords
Factor - Factors are whole numbers which exactly divide another whole number.
Commutative - The commutative law states that you can write the values of a calculation in a different order without changing the calculation; the result is the same. It applies for addition and multiplication.
Associative - The associative law states that it doesn't matter how you group or pair values (i.e. which we calculate first), the result is still the same. It applies for addition and multiplication.