Femi is solving 15 × 14.

Question

She used an area model to help work through each step.

Which calculation did Femi make to get the highlighted partial product?

A rectangle has 1 side of length 10 in green plus 4 in purple, and a second side of 10 in red plus 5 in blue. It is divided into a 10 in red by 10 in green square in the upper left corner, with a 10 in red by 4 in purple rectangle next to it. Beneath the square is a rectangle that is 5 in blue by 10 in green, and next to that a rectangle that is 5in green by 4 in purple. A stacked multiplication and addition example next to it reads 15, with 1 in red and 5 in blue times 14 with one is green and 4 in purple equals 20, plus 40 highlighted in yellow, plus 50 , plus 100 equals 210.
Clear Check

10 × 10

10 × 4

5 × 10

5 × 4

Answer 1

To determine which calculation Femi made to get the highlighted partial product (40), we need to look at the area model described in your question.

In the model, the rectangle is divided into four parts:

1. A square that is \(10 \times 10\) (which gives 100).
2. A rectangle that is \(10 \times 4\) (which gives 40).
3. A rectangle that is \(5 \times 10\) (which gives 50).
4. A rectangle that is \(5 \times 4\) (which gives 20).

Since the highlighted partial product is 40, the correct calculation that corresponds to that partial product is:

10 × 4

Thus, the answer is \(10 \times 4\).