Expressing one number as a fraction of another | Maths

Starter quiz

Match the following to the correct reciprocal.
- 3
  
  ⇔
  
  $1\over3$ ✓
- $5\over2$
  
  ⇔
  
  $2\over5$ ✓
- 1.25
  
  ⇔
  
  $4\over5$ ✓
- $5\over20$
  
  ⇔
  
  4 ✓
- $3 {1\over2}$
  
  ⇔
  
  $2\over7$ ✓
A shop has a sale saving you $1\over3$ . You pay £36 for a sweatshirt. How much was it originally?
- '£54' ✓
$1\over6$ of 150 = $5\over6$ of ______.
- '30' ✓
I think of a number. $5\over8$ of my number is 15. What is my number?
- '24' ✓
The cost of a laptop increases by $1\over8$ . It now costs £675. How much was it originally?
- '£600' ✓
Alex's cat loses $1\over7$ of it's weight. It now weighs 4.2 kg, how heavy was it last year?
- '4.9 kg' ✓