James wants to put colorful backgrounds on the back window glass and the two side window glass panes in the picture above. How much area does he need to cover? Enter your answer as a number only; no units.

Answer:
912 (AND MAKE SURE YOU ADD YOUR YOUR UNITS!)
Step-by-step explanation:
So both side panels are 10 × 12, and the back glass is 12 × 18.
So we are going to do:
2 × (10 × 12) + 12 × 18
= 240 + 216
= 456
But because of the surface area formula we must multiply this by 2!
456 × 2
= 912
So your answer is 912 and whatever your unit is!