Working with Fractions
Aaron and his tortoise
Join Aaron and his tortoise, and see how multiplication helps find distances.
Quick reminder: cut a pizza into 4 equal slices and eat 1: you ate 1/4. The bottom number counts all the equal parts; the top counts the parts you're talking about.
Aaron walks 3 km in 1 hour. In 5 hours: 5 × 3 = 3 + 3 + 3 + 3 + 3 = 15 km. To find a distance, multiply the distance per hour by the hours.
His pet tortoise is much slower: 1/4 km in 1 hour. In 3 hours? Same method: 3 × 1/4 = 1/4 + 1/4 + 1/4 = 3/4 km.
So whole number × fraction is just repeated adding, as with whole numbers. Quick way: multiply only the top; the bottom stays the same. 3 × 1/4 = 3/4.
A farmer gives each of his 5 grandchildren 2/3 acre of land: 5 × 2/3 = 10/3 acres in all.
Try: Tenzin drinks 1/2 a glass of milk every day. How many glasses in a week? In January (31 days)? A team digs 1/8 km of canal a day. How much in a 5-day week?
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