A way of undoing any operation, is using the inverse of the operation. So if you want to ‘undo’ addition you subtract, and if you want to ‘undo’ multiplication you divide.
Hope this helps!!
If asking to simplify 2d + 18
The train is traveling at 165 mph
495/3=165
825/5=165
1155/7=165
1485/9=165
$42.
13/2 = 6.5, 25/4 = 6.25, 42/7 = 6.
