The unitary method

Find the value of one, then multiply up to however many you need.

The question

5 pens cost ₹60. What do 8 pens cost?

The trick

Divide down to a single item, then multiply up to the quantity you want.

Worked example

15 pens cost ₹60
2So 1 pen costs 60 ÷ 5 = ₹12
3So 8 pens cost 12 × 8 = ₹96

So: ₹96

Remember it like this

Go down to one, then up to many. Divide first, multiply second — always that order.

In the exam

Write the 'cost of 1' line explicitly. Examiners award a method mark for it even when the final answer is wrong, and it stops you multiplying when you meant to divide.

Why it works

Price and quantity rise together in a fixed ratio. Once you know the rate for one item, every other quantity is one multiplication away.

Explain this to my childGet the words to teach it, in your language

Try it yourself

0/3 correct

1
4 books cost ₹200. What do 7 books cost? (number only)
4 books cost ₹200. What do 7 books cost? (number only)
2
6 apples cost ₹48. What do 10 apples cost? (number only)
6 apples cost ₹48. What do 10 apples cost? (number only)
3
3 workers finish a job in 12 days. How long for 1 worker? (days)
3 workers finish a job in 12 days. How long for 1 worker? (days)