# Arithmetic Course/Number Operation/Subtraction

## Subtraction[edit]

Subtraction is an operation where one number is deducted from another. It can be represented by

- A - B

## Operation[edit]

- a - b = -b + a
- a - b - c = a - (b + c) = (a - b) - c

## Rules[edit]

Any number subtract zero is equal to the number

- a - 0 = a

Any number subtract to itself equals zero

- a - a = 0

Any number subtract its negative is doubled

- a - (-a) = 2a