Question posted by Tara from the United States:

Grade/Level: Grade 5

Question solved by Model Method: Annie made some tarts. She sold 3/5 of them in the morning and 1/4 of the remainder in the afternoon. If she sold 200 more tarts in the morning than afternoon, how many tarts did she make?

Step 1: Draw 5 boxes to represent the total number of tarts Annie made (5/5) and mark out 3 boxes to represent the number of tarts she sold in the morning (3/5).

Step 2: Since she sold 1/4 of the remainder, i.e., 1/4 of the remaining 2 boxes, we divide the remaining 2 boxes into 4 equal units and mark out 1 unit to represent 1/4 of the remaining tarts.

Step 3: Next, divide the 3 boxes on the left into 6 equal units to make all the unknown units equal. Now we can see that she sold 6 units in the morning and 1 unit in the afternoon.

Since she sold 200 more tarts in the morning than in the afternoon, and 6 units represent the tarts sold in the morning and 1 unit represents the tarts sold in the afternoon, the difference between 6 units and 1 unit must be equivalent to 200 tarts.

Thus,

6 units - 1 unit = 5 units

5 units ---------- 200 tarts

1 unit ---------- 200 tarts / 5 = 40 tarts

10 units ---------- 10 x 40 tarts = 400 tarts

Therefore Annie made 400 tarts altogether.