Starter quiz
- Match the equivalent ratios.
- 4 : 5⇔12 : 15 ✓
- 4 : 3⇔16 : 12 ✓
- 3 : 4⇔15 : 20 ✓
- 5 : 4⇔60 : 48 ✓
- 5 : 3⇔25 : 15 ✓
- 3 : 5⇔24 : 40 ✓
- What symbol separates the parts of a ratio? E.g. the mathematical notation for writing 4 to 5.
- ':' ✓
- Simplify 24 : 36
- '2 : 3' ✓
- In a bag there are only triangles and squares. The ratio of triangles to squares is 3 : 1. There are 60 shapes in total. Who correctly worked out the number of squares?
- Alex "60 triangles, so there are 20 squares because of the ratio is 3 : 1"
- Laura "180 triangles, so there are 40 squares because of the ratio is 3 : 1"
- Andeep "20 triangles, so there are 40 squares because of the ratio is 4 : 1"
- Sofia "45 triangles, so there are 15 squares because of the ratio is 4 : 1" ✓
- Jun "34 triangles, so there are 26 squares because of the ratio is 4 : 1"
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- Chocolates in a box either have red or blue wrappers. The ratio of red to blue is 5 : 4. If the difference between the red and blue chocolates is 3, how many chocolates are in the box?
- '27' ✓
- Chocolates in a box either have red or blue wrappers. The ratio of red to blue is 3 : 2. Andeep eats 2 blue chocolates and now the ratio is 12 : 7. How many blues were in the box originally?
- '16' ✓
Exit quiz
- Which of the following is not the reciprocal of 4?
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-
-
- ✓
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- Use a bar model to calculate of 48
- '18' ✓
- Calculate 60 ×
- '36' ✓
- Which of the following are equivalent calculations for of 72?
- 72 × ✓
- (72 ÷ 9) × 5 ✓
- (72 ÷ 5) × 9
- × ✓
- × 5 ✓
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- Calculate ×
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- ✓
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- Find of 25
- '315' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- The given amount is multiplied by the fraction.
- The given amount may be given in a variety of forms.
- A bar model can represent this situation.
Common misconception
An assumption that you cannot find a fraction greater than 1 of an amount.
Recognising that 'of' and multiplication are equivalent should help with this , as pupils are familiar with multiplying fractions.
Keywords
Reciprocal - The reciprocal is the multiplicative inverse of any non-zero number. Any non-zero number multiplied by its reciprocal is equal to 1.
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