Starter quiz
What number is represented by the factor bug?- '36' ✓
- 50 x 8 = ______
- '400' ✓
- Tick all the factors of 28
- 3
- 4 ✓
- 6
- 7 ✓
- 14 ✓
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- What is the missing factor of 72 from this list? 1, 2, 3, 4, 6, 8, 9, 18, 24, 36, and 72
- '12' ✓
- Put these calculations in order from lowest to highest.
- 1⇔12 × 10 × 1
- 2⇔2 × 14 × 5
- 3⇔16 × (5 × 2)
- 4⇔9 × (4 × 5)
- What is the most efficient calculation for 86 × 5?
- 80 × 6 × 5
- (43 × 2) × 5
- 43 × (2 × 5) ✓
- 2 × (43 × 5)
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Exit quiz
The box is 40 cm long, 10 cm wide and 2 cm deep. What is the volume of the box? ______ cm- '800' ✓
Whose box has the greatest volume?- Lucas whose box is 30 cm long.
- Sam whose box is 36 cm long. ✓
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- Which box has a volume of 60 m?
- The volume of a cuboid is 105 cm. The height is 5 cm and width is 3 cm. What must the missing length be? ______ cm
- '7' ✓
- The volume of a warehouse is 216 m. The height is 6 m. What could the length and width be?
- 7 m and 6 m
- 9 m and 4 m ✓
- 9 m and 3 m
- 18 m and 2 m ✓
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- A box of tissues has a length of 25 cm. The volume of the pack is 900 cm. What could the width and height of the box be?
- 12 cm and 3 cm ✓
- 8 cm and 6 cm
- 9 cm and 4 cm ✓
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- To simplify a multiplication calculation, you can change the order of the factors.
- To simplify a multiplication calculation you can group the factors in different ways.
Common misconception
Pupils struggle to understand that a 3 factor calculation problem with two unknown factors can be represented as a 2 factor calculation with one unknown factor.
Spend time manipulating 2 factor calculations into 3 factors and vice versa. Once pupils are confident with this, apply this to a context where the numbers are kept simple to support pupils to see the structure of the problems.
Keywords
Represent - To represent something is to show it in a different way.
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.
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.