Inverse operations are two operations, each of which "undoes" the other. For example, addition and subtraction are inverse operations:
|4 + 3||=||7|
|7 - 3||=||4|
As can be seen, adding 3 to 4 and then subtracting 3 from the sum leaves us where we started, with 4.
Multiplication and division are also inverse operations:
|6 × 5||=||30|
|30 ÷ 5||=||6|
As with addition and subtraction, it can be seen from this example that multiplication and division essentially cancel each other out, and multiplying and then dividing a starting value by the same value, results in the same starting value at the end of the process.
See also fact family.