Addition is actually adding two sets together to become one set.
Subtraction: Divide a set into two parts.
Subtraction formula
1, minuend-subtrahend = difference
2. Difference+Minus = Minus
3, the minuend-difference = reduction
Subtraction correlation characteristic
1, inverse exchange rate: subtraction is inverse exchange. If A and B are any two numbers, then
(A-B) =-(B-A)
2. Anti-association rule: subtraction is anti-association. When trying to redefine subtraction, then
a-b-c=a-(b+c)