FAST Math Grade 3 key terms

The value a digit has because of the position it holds in a number. In 4,582, the 5 is worth 500 because it sits in the hundreds place.

A number written with digits in the usual way, one digit per place. For example, three thousand forty-six is written as 3,046 in standard form.

A number broken apart to show the value of each digit. The number 3,046 in expanded form is 3,000 + 40 + 6.

A number written out in words instead of digits. The number 708 is written in word form as seven hundred eight.

Replacing a number with a nearby number of a chosen place value. You look at the digit to the right: 4 or less stays the same, 5 or more rounds up.

An answer that is close to the exact amount, often found by rounding first. Estimating helps you judge whether an exact answer is reasonable.

Solving a problem in your head without writing out the steps or using a calculator. Making tens and using known facts are common strategies.

Rules that let you regroup or reorder numbers without changing the result. Examples include the commutative property for addition and the associative property for grouping.

A group of related number sentences that use the same three numbers. For 3, 4, and 12, the family includes 3 × 4 = 12 and 12 ÷ 4 = 3.

Finding the total when you combine equal groups. Four groups of 3 objects make 12, so 4 × 3 = 12.

Splitting a total into equal shares or finding how many equal groups fit inside a total. Twelve shared into 4 groups gives 3 in each group.

The answer to a multiplication problem. In 6 × 7 = 42, the number 42 is the product.

A number that is multiplied by another number in a multiplication sentence. In 6 × 7 = 42, both 6 and 7 are factors.

The answer to a division problem. In 42 ÷ 6 = 7, the number 7 is the quotient.

The amount left over when a number cannot be divided evenly. Dividing 14 by 4 gives 3 with a remainder of 2.

Objects arranged in equal rows and columns, used to show multiplication. A 3 by 4 array has 12 objects and shows 3 × 4 = 12.

Sets that each contain the same number of objects. Equal groups are the foundation for understanding multiplication and division.

A number that names part of a whole or part of a set. It is written with a numerator on top and a denominator below, such as three fourths.

The top number of a fraction. It tells how many equal parts are being counted or described.

The bottom number of a fraction. It tells how many equal parts the whole has been cut into.

A fraction with a numerator of 1, such as one half or one sixth. It names a single equal part of a whole.

Different fractions that name the same amount. One half and two fourths cover the same part of a whole, so they are equivalent.

A straight line marked with numbers at equal spacing. It can show whole numbers, fractions, and where a value falls between two numbers.

A counting number starting at zero, with no fractions or decimals. Examples are 0, 7, and 250.

A number sentence with an equals sign showing that two sides have the same value. For example, 8 + 5 = 13 is an equation.

The missing value in a number sentence, often shown with a letter or a blank. In 5 × ___ = 20, the unknown is 4.

A combination of numbers and operation signs without an equals sign. For example, 12 + 7 is an expression that can be evaluated to 19.

The distance all the way around the outside of a shape. You find it by adding the lengths of every side.

The amount of flat space a shape covers, measured in square units. A rectangle 3 units by 4 units has an area of 12 square units.

A square that is one unit long on each side, used to measure area. Counting square units inside a shape tells you its area.

A closed flat shape made of straight sides that do not cross. Triangles, squares, and hexagons are polygons.

A polygon with exactly four straight sides. Squares, rectangles, rhombuses, and trapezoids are all quadrilaterals.

An angle that makes a square corner, measuring exactly 90 degrees. The corners of a rectangle are right angles.

The amount of time that passes between a start time and an end time. From 9:15 to 10:00, the elapsed time is 45 minutes.

The amount of matter in an object, often measured in grams and kilograms. Mass tells how heavy something is.

The amount of space a liquid or object takes up, often measured in liters and milliliters. Volume can also mean the space inside a solid figure.

A graph that uses small pictures or symbols to show data. A key tells how many each picture stands for.

A graph that uses rectangles of different lengths to compare amounts. The taller the bar, the greater the value.

A number line with marks stacked above each value to show how often it appears. It is useful for showing measurements.