Elementary arithmetic: Difference between revisions

Revision as of 21:38, 8 April 2005

Revision as of 21:41, 8 April 2005

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Symbolically, addition is represented by the "plus sign": <big> + </big>. So the statement "three plus five equals eight" can be written symbolically as

:<math> 3 + 5 = 8.\ </math>

The order in which two numbers are added does not matter, so that,:<math>3 for+ example,5 three= plus5 four+ equals3 four= plus three8</math. This is the [[commutative]] property of addition.

To add a pair of digits using the table, find the intersection of the row of the first digit with the column of the second digit: the row and the column intersect at a square containing the sum of the two digits. Some pairs of digits add up to two-digit numbers, with the tens-digit always being a 1. In the addition algorithm the tens-digit of the sum of a pair of digits is called the "carry digit".