Before we get started, it is good to remember PEMDAS - the acronym that tells you the order to carry out equations.
P = parentheses
E = exponents
M = multiplication
D = division
A = addition
S = subtraction
Knowing this, we should start by doing the equations <em>within </em>each parentheses.
![(2) *(10)](https://tex.z-dn.net/?f=%282%29%20%2A%2810%29)
So we did the addition and subtraction pieces within each group leaving us with the above equation. Now let's multiply:
![(2)*(10) = 20](https://tex.z-dn.net/?f=%282%29%2A%2810%29%20%3D%2020)
20 is the answer.
12 hundreds+8 tens+7 ones =
12*100 + 8*10 + 7*1 =
1200 + 80 + 7 =
1287 ← answer
I believe its 3 because the range is the distance between the highest and lowest number