How to move part of a number to another cell in Google Spreadsheets?

Question

Google Sheets

For example, I need that after adding 100 + 100, the number 180 is always written into the cell, and the rest 20 into another.

Answer 1

1) In the cell format, write "180" - this will be displayed instead of the value
2) Subtract 180 from the cell where (100 + 100) and write where the difference is needed.
Demo table