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Grade 5 Math · Level 2, Fractions as Numbers

Multiply Fractions

How the lesson starts: Multiply Fractions

1. Grandpa Theo's garden

   Grandpa Theo has a garden. 3/4 of it is for vegetables. He wants carrots in 2/3 of the vegetable part. How much of the whole garden is carrots? That's a fraction of a fraction. Let's dig in!

2. A part of a part

   Start small: 1/3 of 1/4. Here's 1/4 of the garden. Cut that fourth into 3 equal strips and take one. How big is that strip? 12 of them would fill the garden. So 1/3 of 1/4 = 1/12. And 1 × 1 = 1, 3 × 4 = 12!

3. Grandpa's carrots

   Now 2/3 of 3/4. Of means multiply: 2/3 × 3/4. Top times top: 2 × 3 = 6. Bottom times bottom: 3 × 4 = 12. So 6/12, which simplifies to 1/2. Half the garden is carrots! Watch out: no common denominator needed.