In teaching math, you have to start somewhere.
Perhaps this?
(360 + a) / 5 = 92
⇒ 360 + a = 460
⇒ a = 460 - 360 = 100
Yes, very good!
Perhaps this?
(360 + a) / 5 = 92
⇒ 360 + a = 460
⇒ a = 460 - 360 = 100
Yes, very good!