Question

Which number sentence can be used to find three times the sum of twelve and six? Which number answer is correct?

A) x= 3 x 12 x 6
B) x=3(12+6)
C) x=3+(12x6)
D) x=3x12+6

Answer 1

The answer is B) x=3(12+6).

Answer 2

Answer: Choice B

Reason:

12+6 represents "the sum of 12 and 6". The sum is the result of adding two or more numbers.

Then the "three times" means we'll triple the result of 12+6

So we stick a 3 out front to get 3(12+6)

Be sure to avoid the mistake of saying 3*12+6 which isn't correct. Choice D is a trick answer. We aren't tripling the 12 only. We are tripling ALL of (12+6), so we're going to triple the 12 and the 6 as well

3(12+6) = 3*12 + 3*6 because of the distributive property

One way to think of it is to say:

3(12+6) = (12+6)+(12+6)+(12+6) = (12+12+12) + (6+6+6) = 3*12+3*6