Question

Which expression has the same value as 20 − 4 ⋅ 3

a. 20 − (4 ⋅ 3)
b. (20 − 4) ⋅ 3
c. 20 + 4 − 3
d. 20 ⋅ 4 − 3

Answer 1

Answer: A: 20 - (4 x 3)

Explanation:

In the end, the final answer is 8, so we need to see which one of these options give us 8. As seen, we first must solve the multiplication, and the first option, A, solves the multiplication first because it is in parenthesis, which gives us 8, so the correct answer is A.

Answer 2

a. 20 - (4 ⋅ 3)

Explanation:

PEMDAS: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction

Please note that multiplication 4 ⋅ 3 will happen before the subtraction -

If we add parentheses, we introduce a new "order". But if the parentheses are around the first operation we perform, the order stays the same!

This means that answer a. must be correct.

We verify:

20 − 4 ⋅ 3 = 20 - 12 = 8

a. 20 − (4 ⋅ 3) = 20 - 12 = 8

b. (20 − 4) ⋅ 3 = 16 ⋅ 3 = 48

c. 20 + 4 − 3 = 21

d. 20 ⋅ 4 − 3 = 80 - 3 = 77