1 foot = 12 inches is a ratio. Going to a smaller unit gives more of them: multiply. Going to a bigger unit gives fewer: 36 inches ÷ 12 = 3 feet.
Worked example
1 quart = 2 pints. How many pints are in 7 quarts?
Answer:14 pints
Each quart is 2 pints. 7 × 2 = 14 pints.
For grown-ups: Unit conversion by ratio reasoning. Below: three problems to try with the worked answers, and a free printable sheet. Children can practise the same skill as a game, with no sign-up and no ads.
CCSS 6.RP.A.3d
What this practises, for teachers
Practices unit conversion by ratio reasoning (6.RP.A.3d). A printable sheet with its answer key, worked answers on the page, no accounts.