411 REFERENCE · Wikibooks
Arithmetic Course/Number Operation/Subtraction
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Subtraction
Subtraction is an operation where one number is deducted from another. It can be represented by
A - B
Operation
a - b = -b + a
a - b - c = a - (b + c) = (a - b) - c
Rules
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