For the equation to work, you have to have the same number on both sides of the equal sign
so to find ?, you can do:
13 - 2 = 12 - ? Simplify
11 = 12 - ? Subtract 12 on both sides
-1 = - ? Multiply -1 on both sides
1 = ?
You left 20% tip. all you do is divide the tip,0.60, by the total , 3.
You lose 20%.
if it were going up to 72 to 90 it would be a 25% increase
Each pack of batteries cost $21 each.
And then you have $63.
The operation to be used: Division.
63 ÷ 21 ==
Answer: 3
= You can buy 3 packs of batteries with your $63.