## addition
The numbers which are added are called summands. For example,
4 (a summand) + 3 (another summand) = 7 (sum). ## Addition of fractionsFractions can be added directly only if they have equal denominators, e.g., 3/17 + 4/17 = 7/17.If fractions with unequal denominators are to be added they must first be brought to their least common denominator. ## Addition of literal numbersIdentically-named numbers can be added (and subtracted) by adding the coefficients:2summands may be interchanged (commutative law): With more than two summands, brackets may be inserted (associative law):
## Addition of directed numbersNo further rule is needed for the addition of positive numbers:to add one negative number to another, its absolute value is subtracted:
## Addition of powers and surdsPowers and surds must be treated like literal numbers for the purposes of addition, e.g.,
## Addition of complex numbersIn adding complex numbers the real and imaginary parts must be added separately, e.g.,(5 + 3 ## Addition in terms of setsThe addition of positive numbers can best be defined in terms of set theory; if one considers setA to contain 4 elements, set B to contain 5 elements, then A U B (see union)
contains 9 elements; i.e., 4 + 5 = 9. The addition of negative numbers is
equivalent to subtraction in that a + (-b) is equivalent
to a - b. ## Related categories• ALGEBRA• ARITHMETIC | |||||||

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