Question

batteries are sold in packets and boxes. There are 4 batteries in a pack. There are 20 batteries in a box. Derek buys box of batteries he takes T batteries out of the box write down an expression in terms of T for the number of battery is left in the box.

Answer 1

An equation to represent this problem is:
20(4)-t = x

Answer 2

20*4-t=x is the equation according to me.
forgive me if it is wrong