| A | B |
| Decimal | a number that has at least one place to the right of the decimal point. |
| Denominator | in fraction, the number below the fraction bar. |
| Diagonal | a line segment that connects two nonconsecutive vertices of a polygon. |
| Diameter | a line segment that has both endpoints on the circle and passes through the center of the center of the circle. |
| Distributive Property | the rule that states that multiplying a sum by a number gives the same results as multiplying each added by the number and than adding the products. |
| Edge | the line segment formed by the intersection of two faces of a solid figure. |
| Equation | a mathematical sentence with an equal sign. |
| Equivalent Fractions | two or more fractions that have equal values. |
| Estimate | a number that is close to the exact amount. |
| Exponent | tells how many times multiply a number by itself. |
| Expression | a combination related by an operation or operations. |
| Face | the flat surface of a three-dimensional figure. |