The Columbia Encyclopedia, Sixth Edition. 2001-07.
distributive law
In mathematics, given any two operations, symbolized by * and [symbol], the first operation, *, is distributive over the second, [symbol], if a*(b[symbol]c)=(a*b)[symbol](a*c) for all possible choices of a, b, and c. Multiplication, ×, is distributive over addition, +, since for any numbers a, b, and c, a×(b+c)=(a×b)+(a×c). For example, for the numbers 2, 3, and 4, 2×(3+4)=14 and (2×3)+(2×4)=14, meaning that 2×(3+4)=(2×3)+(2×4). Strictly speaking, this law expresses only left distributivity, i.e., a is distributed from the left side of (b+c); the corresponding definition for right distributivity is (a+b)×c=(a×c)+(b×c).
