The unitary method: shopping at the kirana pasal
Rice, sugar, notebooks and eggs come in packs at a price. Find the price of one by dividing, then the price of as many as you want by multiplying.
Core concept
In short: Find the price of one, then use it to find the price of many.
In the unitary method we first find the value of one unit by dividing, then the value of any number of units by multiplying
Topic: Unitary method
At the kirana pasal, rice is sold at Rs 400 for 5 kg. How much would 12 kg cost? The unitary method answers this in two steps. First find the price of one unit (one kilogram, one notebook, one egg) by dividing: Rs 400 ÷ 5 = Rs 80 for 1 kg. Then find the price of as many as you want by multiplying: Rs 80 × 12 = Rs 960 for 12 kg. "Unitary" comes from "unit", meaning one. The same idea works for wages, distances and time: if 4 days of work earn Rs 3200, one day earns Rs 800.
What you will learn
- Find the value of one unit by division.
- Find the value of many units by multiplication.
- Solve everyday problems about prices with the unitary method.
Before you start
- Know how to multiply and divide whole numbers.
Materials
- A price list from a local shop
Equipment
- A notebook and pencil
Procedure
- Find the price of 1 kg of rice.
- Find the price of 12 kg of rice.
- Find the price of 8 notebooks and of 30 eggs.
How this simulation is simplified
- Every unit costs the same, however many you buy (no discount for buying more).