Class 8 : Unitary Method

Mathematics Explorer

Unitary Method & Variation — Class 6 (CDC Nepal)

1. Unitary Method

"Unitary" means 1. We first find the value of one item, then calculate for many.

Example: If 5 apples cost Rs. 100, find the cost of 1 apple first (Rs. 20), then find the cost for 8 apples.

2. Direct Variation

When one thing increases, the other also increases at the same rate.

Example: More petrol in a bike = More distance traveled. (Both go UP together).

3. Indirect Variation

When one thing increases, the other decreases.

Example: More workers on a building = Less time to finish. (One UP, one DOWN).

Live Simulation

Select Scenario: Direct: Apples vs Cost (Rs.) Indirect: Workers vs Days

Number of Apples: 5

Rate: 1 apple costs Rs. 25

Number of Workers: 4

Work: 1 person takes 40 days

Step-by-Step Solution:

Items	Value

Test Your Knowledge

Watch Out! Common Errors

• ✗
  Wrong Choice: Thinking that more workers take more time.

  Correct: It's Indirect Variation. More people means the work finishes faster (less time).

• ✗
  Step Skipping: Trying to find the cost of 10 items without finding the cost of 1 item first.

  Tip: Always find the Unit Value (value of 1) first to avoid calculation mistakes.

• ✗
  Calculation Confusion: In Indirect Variation, we multiply the initial values, we don't divide like in Direct Variation.