Addition.
Addition.—Operation which consists in taking in any order all the units and portions of units of several numbers and forming with them a single number called their Sum or Total.
Addition of Long Columns of Numbers.—When long columns of numbers are to be added, the student should endeavor to add more than one figure at a time. He may pick those which aggregate 10, 15, 20, etc., and add the intermediate figures when convenient.
Sign of Addition.—The sign of addition is the horizontal-vertical or Roman cross + placed between all the numbers to be added; it is read Plus.
To Prove an Addition.—The shortest way to prove an addition is to do it over again from bottom to top.
Sign of Equality.—The sign of equality is two short equal horizontal parallels =; it reads Equal.
Subtraction.
Subtraction.—An operation which consists in taking from a number called minuend (m) all the units and parts of units contained in another number called subtrahend (s). The result is called the difference (d) of the two numbers or the remainder of their subtraction.
Sign of Subtraction.—The sign of subtraction is a horizontal dash - placed between the minuend, written first, and the subtrahend. Thus: 84 - 38 = d; 84 - 38 = 46. Generally m - s = d.
To Prove a Subtraction.—Add from bottom to top the difference and the subtrahend; the sum must equal the minuend.