subtract

verb

Etymology: Borrowed from Latin subtractus, perfect passive participle of subtrahō (“to draw from beneath; withdraw, remove”); from sub (“under”) + trahō (“to draw, pull, drag”).

1. To remove or reduce; especially to reduce a quantity or number.

   “If you subtract the $100 for gas from the total cost, it was a fairly inexpensive trip.”

   “I could add and subtract and multiply and divide, but I entered the wilderness when words became equations. […] The axioms of arithmetic imply that when you expand (a + b)², for example, you get a² + 2ab + b² in the following way: (a + b)² is equal to (a + b)(a + b). Each term in one parentheses multiplies the terms in the other: a × a = a² ; a × b = ab; b × a = ab; b × b = b². Combining the terms, a² + ab + ab + b² = a² + 2ab + b². In a similar way, a² – b², a squared number subtracted from another squared number, called a difference of squares, becomes (a – b)(a + b), which becomes a² + ab – ab – b², which is a² – b².”