Question

The model shows the expression 20 + 16.

A model with 4 rows of 5 squares and 4 rows of 4 squares.

Which expression is equivalent to this sum?
4 (5) + 4
4 + 5 + 4
4 (5 + 4)
5 (4 + 4)

Answer 1

4 (5 + 4)

Explanation:

1. the model show 20 + 16 which = 36

2. the first example 4 (5) + 4 which equals 20 + 4 or 24.

3. the second example 4 + 5 + 4 which equals 9 + 4 or 13.

4. the third example 4 (5 + 4) , using order of operations, equals 4 x 9 and that equals 36.

5. the last examples 5 (4 + 4) is 5 x 8 which is 40.

That is why the third example is correct!

Answer 2

4(5+4)

Explanation:

20 + 16 = 36

Think of PEMDAS (In this scenario you have parenthesis and addition)

4(5+4) = 20 + 16

4 (9) = 36

36 = 36

While looking at the other options:

4 (5) + 4 = 24

4 + 5 + 4=13

5 (4 + 4)= 40