Find the missing number □ in the equation □ × 38 = 56 − 14. Give your answer as a mixed number in simplest form.
- Find the value of 56 − 14.
- Hence, find the missing number □.
Need a hint?
In (a), change both fractions to the same denominator before subtracting. In (b), dividing by a fraction means multiplying by its reciprocal.
Worked answer
- (a) Write both fractions with denominator 12: 10/12 − 3/12 = 7/12.
- (b) □ = 7/12 ÷ 3/8.
- Multiply by the reciprocal: 7/12 × 8/3 = 56/36.
- Simplify: 56/36 = 14/9 = 1 5/9.
Answer: 1 5/9
The mistake this question tests
Habit
Calculation slip
Pupils often subtract the denominators as well, or multiply 7/12 by 3/8 instead of dividing, which gives a much smaller answer.
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