You can find the numerical part of the answer because it is the same on the right side.
For example:
¹ <<==== Regrouped
89
+
67
---------
146 <<=== I had to press space so I could position it.
So that also happens in subtraction, the left side can be found by doing the same steps in the right column.
For example:
67
- <<=== this time there was no regrouping
12
-------
55
