Find x: subtraction
About this exercise
Solving a one-step equation built on a subtraction.
Example problems
A few of the problems this exercise asks. The printable worksheet holds ten fresh ones.
- x - 4 = 6
- x - 2 = 2
- 12 - x = 7
- 11 - x = 4
Try it yourself first — open a section below only if you get stuck.
How to solve it
If the unknown is being reduced, add the number to both sides. If the unknown is what is being taken away, it equals the first number minus the result.
Worked example
From x - 4 = 9, adding 4 gives x = 13. From 12 - x = 6, the unknown is 12 - 6 = 6.
Common mistake
Treating both forms the same way. In 12 - x = 6 you cannot simply add 6 to each side and stop.