E

equation

A true number sentence can also be called an equation because the amounts on both sides of the equal sign are the same.

pages 132–135

equilateral

A shape with all sides and all angles equal.

pages 283–284

equivalent

The same as or equal to.

pages 64–68, 76–79, 216–220, 238–239, 461, 465, 518–525, 526–536

equivalent fractions

Fractions that represent the same part of the whole. For example, , , and are equivalent to each other, and and are equivalent to each other.

pages 64–68, 76–79, 216–220, 238–239, 461, 465, 518–525

equivalent ratios

Ratios that are equal or represent the same number.

pages 216–220, 238–239, 465, 518–525, 526–536

estimate

1. (verb) To find about how many.
2. (noun) An approximate number.

pages 5–8, 40, 86–88, 89–90, 100–104, 108–110, 136–143, 153, 156, 161–163, 201–202, 273, 294–297, 306–309, 335–338, 402, 406–408, 417–418, 458–459, 470–472, 479, 501, 516, 559, 577, 580–581

expanded form

A number shown expanded into its place value parts. For example: 423 = 400 + 20 + 3. The examples show how to use expanded form to add, subtract, and multiply.

pages 122, 124–128, 133, 167–168, 175–176, 370–373, 407, 416

exponent

The number of times the base is multiplied by itself. In 3⁴ = 3 × 3 × 3 × 3 = 81, the 3 is the base and the 4 is the exponent. The 3 is multiplied by itself 4 times. (See also base.)

pages 144–155, 443–445, 446–448

extrapolate (extrapolation)

Using patterns in data to make predictions or to estimate values that lie beyond the range of values in the set of data. (See also interpolate.)

pages 521, 545, 549, 555