Simple ratios: how many times

Japanese school year: Elementary 4

What you learn

You will learn how to express the relationship between two quantities by finding how many times greater one is than the base amount. This concept is useful when comparing lengths, weights, or prices in everyday situations. Prior understanding of multiplication and division concepts is essential for mastering this comparison.

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Key points

This formula is used to calculate the ratio $p$ (how many times larger something is relative to a base). Divide the compared amount $a$ by the base amount $b$ .

p = a \div b

This formula is used to find the compared amount $a$ from base amount $b$ and ratio $p$ . It is calculated as base amount $b \times$ ratio $p$ .

a = b \times p

This formula is used to find the base amount $b$ from the compared amount $a$ and ratio $p$ . It is calculated as compared amount $a \div$ ratio $p$ .

b = a \div p

This is a tip for identifying the base amount in word problems. The quantity that follows phrases like "times as much as..." or "relative to..." represents the reference base amount.

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Practice 1Coming soon