Telling a student that "in addition you can switch the order" is bad math education. Uniformity of design is pertinent -->
5 cows plus (add) 3 cows is 8 cows
5 cows minus (remove) 3 cows is 2 cows
The alteration should always follow base. 16:36:18 208 020 2020-10-13 16:36:18