Information that is collected by counting, measuring, asking questions, or observing that is usually organized for analysis Data display.A way to visually organize data Decagon.A polygon with 10 sides Decimal.A number in a number system based on 10 (also known as base-ten system or Hindu-Arabic system) Decimal fraction.A number written in standard base-10 notation Decimal notation. Representation of a fraction or other real number using the base ten and consisting of any of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and a decimal point Decimal point.A demarcation between whole numbers and numbers less than one Decompose.The process of separating into smaller parts Denominator.The number of equal parts making up a whole (the bottom number in a fraction) Diameter.A line segment that passes through the center of a circle and has endpoints on the circle Difference.The space between the value of two numbers on a number line (the result of subtracting one number from another) Digit.Any one of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 Digital root.The result of adding digits in a number until only one digit remains Dilation. A transformation that moves each point along the ray through the point emanating from a fixed center, and multiplies distances from the center by a common scale factor Directrix. A fixed line used in the description of a curve or surface Distributive property of multiplication.A property indicating a special way in which multiplication is applied to addition or subtraction of two or more numbers in which each term inside a set of parentheses can be multiplied by a factor outside the parentheses. For example,4(2 + 3) = 4⋅2 + 4⋅35(9−3) = 5∙9−5⋅3Division.The operation of making equal groups to find out how many in each group or how many groups (component parts: dividend ÷ divisor = quotient)

Page | 99 Double number line diagram. Two number lines with different scales intended to organize and compare values Edge.It is the line segment that joins two vertices where two faces of a solid shape intersect Ellipse.A curved line forming a closed loop, where the sum of the distances from two points (foci) to every point on the line is constant End-to-end vector addition. Added or subtracted graphically by laying them end to end on a set of axes Equal.Having the same value Equation.A mathematical sentence where the left side of the equal sign has the same value as the right side of the equal sign Equilateral.A polygon with all sides congruent Equilateral triangle.A triangle whose sides are all the same length Equivalence. The condition of being equal or equivalent in value, worth, function, etc.Equivalent.Having the same value Estimate.To find a number close to an exact amount Even number.Whole numbers that are divisible by 2; even numbers have 0, 2, 4, 6, or 8 in the ones place Expanded form. A multi-digit number is expressed in expanded form when it is written as a sum of single-digit multiples of powers of ten. For example, 643 = 600 + 40 + 3.