decimal: A fraction with an unwritten denominator of 10 indicated by the decimal point.

degree of an expression: The highest power occurring in an expression.

denominator: The bottom number in a fraction.

difference: The result of subtraction.

digit: Numerals from zero through nine, so called because they were originally counted on the fingers.

distributive property: A characteristic of multiplication and addition that allows for the multiplication of each individual term in a grouped series by a term outside of the grouping without changing the value of the expression.

dividend: A number to be divided by another number.

divisible: A number that can be divided by another number with no remainder.

double root: A solution that appears twice when solving an equation because the related factor appears twice in the factored form. For example, in (y – 2)(y – 2) = 0, y = 2 is a double root or solution. In (y – 2)(y – 2)(x + 3) = 0, y = 2 is still a double root or solution.