Checking and securing finding a fraction of a given amount | Maths

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"
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' ✓

Which of the following is not the reciprocal of 4?
- $1\over4$
- $5\over20$
- $8\over32$
- $9\over35$ ✓
- $11\over44$
Use a bar model to calculate $3\over8$ of 48
- '18' ✓
Calculate 60 × $3\over5$
- '36' ✓
Which of the following are equivalent calculations for $5\over9$ of 72?
- 72 × $5\over9$ ✓
- (72 ÷ 9) × 5 ✓
- (72 ÷ 5) × 9
- $5\over9$ × ${8\times9}\over{1}$ ✓
- $72\over9$ × 5 ✓
Calculate $2 {{3} \over {5}}$ × $2\over7$
- $16\over35$
- $26\over35$ ✓
- $36\over35$
- $46\over35$
Find $12 {{3} \over {5}}$ of 25
- '315' ✓

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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.

Reciprocal - The reciprocal is the multiplicative inverse of any non-zero number. Any non-zero number multiplied by its reciprocal is equal to 1.