Rates: cheat sheet

Number Foundations · The words and methods from the lessons, with an example of each.

rate

A rate compares quantities with different units (km per h, $ per kg); a ratio compares the same kind. 1 km/h = 1000 m ÷ 3600 s: divide by 3.6 for m/s.

\text{unit rate} = \text{first quantity} \div \text{second quantity}

At 60 km per hour, 2.5 hours matches 150 km

using a rate

Write the units in: km ÷ km/h = h. Then check the size makes sense.

\text{total} = \text{rate} \times \text{amount} \qquad \text{amount} = \text{total} \div \text{rate}