Question posted by Jil from Singapore:

Each bought a pair of skates at the same price.
After their purchase, Andrew had five times as much money as Brett.
How much did each pair of skates cost?

Step 1: We will start by drawing the "After" model, i.e., the model to represent what happens after the purchase of the skates. Draw 5 boxes and 1 box to represent how much money Andrew and Brett had left respectively after buying the skates. Step 2: Draw 2 equal boxes to represent the money spent on skates by both of them. This is the "Before" model. Step 3: Label the model to show the amount of money each of them had before buying the skates, namely \$268 and \$172. Step 4: From the model, we can see that the difference between \$268 and \$172 is represented by 4 boxes or 4 units. We label the 4 units with a "?". Therefore,

4 units ----------> \$268 - \$172 = \$96

1 unit -----------> \$96 / 4 = \$24

From Brett's portion of the model, we can see that,

Cost of a pair of skate = \$172 - \$24 = \$148