Anyone know inverse operations, cause I am confused, I looked online and it said Example: 20 + 9 = 29 can be reversed by 29 − 9 = 20 (back to where we started)
And the other way around:

Example: 15 − 3 = 12 can be reversed by 12 + 3 = 15 (back to where we started)
so like when do we do the 2nd way or can we just do either one of them???

For inverse operations, it helps make solving equations easier. Say if you'd rather add than subtract, then you can do the inverse of a negative equation.

Inverse operations are also very helpful for linear equations.

To find the inverse of an equation, we change the plus sign to a negative sign. Then, we switch the first number and the answer.

Ex:

13 - 2 = 11    (now change plus to minus)

13 + 2 = 11      (not the answer yet)

Now we switch the first number with the answer!

11 + 2 = 13

Hope this helped, I tried to explain it easily.

it would rotate about 180 degrees.