Subtraction is the arithmetic operation for finding the difference between two numbers. The special names of the numbers in a subtraction expression are, minuend − subtrahend = difference. The expression 7 − 4 = 3 can be spoken as "seven minus four equals three", "seven take away four leaves three" or "four from seven leaves three".
If the minuend is less than the subtrahend, the difference will be a negative number. For example, 17 − 25 = ( −8 ). We can say this as, "Seventeen minus twenty-five equals negative eight". This is how cash registers determine the change you receive when you pay with more money than your purchase costs.
Adapted from Simple English Wikipedia