Bridge: Multiply Fractions & Scaling

How the lesson starts: Bridge: Multiply Fractions & Scaling

Tess's invention lab
Hi, inventor! Meet Tess and her Zoom-o-Matic, a machine that multiplies by fractions. But first, snack time! Half of her brownie tray has frosting. Tess eats 1/3 of the frosted half. What part of the whole tray is that?
Brownie grid
Here's the tray, cut into 2 columns and 3 rows. Shade 1 column blue: that's 1/2, the frosted half. Shade 1 row yellow: that's 1/3. The green square is where they overlap. That's 1 square out of 6. So 1/2 × 1/3 = 1/6!
Let's work one out
Tess makes a mini map: 4/5 × 3/4. Multiply the tops: 4 × 3 = 12. Those are the green squares. Multiply the bottoms: 5 × 4 = 20. That's all the squares. That makes 12/20. Simplify: divide top and bottom by 4. 12/20 = 3/5!