Relative quantities

Distinguish the reference amount from the amount compared and find their ratio.

Meaning

A relative quantity is the comparison amount divided by the reference amount. It can compare part and whole, or two amounts neither of which contains the other.

Example

If you read 8 books last month and 12 this month, this month's amount relative to last month's is Divide both amounts by the reference 8 to make it 1. Twelve books are 1.5 times that reference, and 8×1.5=12 checks the original amount.The reference amount cannot be zero, and the ratio can exceed 1. Choose the reference first.

Practice for this concept

Scope and references

Topics

Reference and comparison amounts, parts and wholes, calculating relative quantities

Learning goal

Distinguish the reference amount from the amount compared and find their ratio.

Helpful background

Distinguish whole and part and connect division with fraction notation.

Part-to-whole ratios

Does not cover every situation involving ratios and relative quantities.

Reference and comparison quantities

Does not include solving proportions or proportional allocation.

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