FAST Math Grade 4 key terms

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

A number written with digits only, in the usual way, such as 3,706 or 48. It is the everyday way of writing a number.

A number broken apart to show the value of each digit, written as a sum. For example, 3,706 is written as 3,000 + 700 + 6.

A number written out using words instead of digits, such as three thousand seven hundred six. Hyphens and commas follow the usual writing rules.

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

An answer that is close to the exact amount, found by rounding or using friendly numbers. Estimates help you judge whether an exact answer is reasonable.

Numbers that are easy to compute with mentally, often used to estimate. For 4,178 ÷ 6, you might use 4,200 ÷ 6 because those numbers divide evenly.

A whole number that divides another whole number with no remainder. The factors of 12 are 1, 2, 3, 4, 6, and 12.

The result of multiplying a whole number by 1, 2, 3, and so on. The multiples of 4 are 4, 8, 12, 16, and so on.

A whole number greater than 1 whose only factors are 1 and itself, such as 2, 3, 5, 7, and 11. The number 1 is not prime.

A whole number greater than 1 that has more than two factors, such as 8, whose factors are 1, 2, 4, and 8.

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

The answer to a division problem. In 56 ÷ 8 = 7, the quotient is 7.

The amount left over when a whole number cannot be divided evenly. Dividing 17 by 5 gives a quotient of 3 and a remainder of 2.

The number being divided in a division problem. In 56 ÷ 8, the dividend is 56.

A number that names part of a whole or part of a set, written as one number over another. In 3/4, the whole is split into 4 equal parts.

The top number of a fraction. It tells how many equal parts are being described, as the 3 in 3/4.

The bottom number of a fraction. It tells how many equal parts the whole is divided into, as the 4 in 3/4.

Fractions that name the same amount even though their numbers differ. For example, 1/2 and 2/4 are equivalent because they cover the same part of a whole.

A fraction written with the smallest possible whole numbers, where the numerator and denominator share no factor other than 1. For example, 4/8 becomes 1/2.

A number that is a multiple of the denominators of two or more fractions, letting you compare or add them. For 1/3 and 1/4, 12 is a common denominator.

A number made of a whole number and a fraction, such as 2 1/3. It can be rewritten as a fraction greater than one.

A number written with a decimal point to show parts smaller than one, such as 0.75. The digits after the point name tenths, hundredths, and so on.

The dot in a decimal number that separates the whole-number part from the fractional part. In 12.6, it separates 12 ones from 6 tenths.

The place one step to the right of the decimal point, where each digit means that many parts out of ten. In 0.7, the 7 means seven tenths.

The place two steps to the right of the decimal point, where each digit means that many parts out of one hundred. In 0.45, the 5 means five hundredths.

A mathematical phrase built from numbers, operation signs, and sometimes letters, with no equals sign. Examples are 8 + 3 and 5 × n.

A mathematical sentence stating that two expressions have the same value, joined by an equals sign. For example, 4 × 6 = 24.

A letter or symbol that stands for a number you do not know or that can change. In n + 5 = 12, the letter n is the variable.

The value you must find to make an equation or statement true. In 7 × ? = 42, the unknown is 6.

The agreed rules for which operation to do first in a number sentence: work inside parentheses, then multiply and divide left to right, then add and subtract left to right.

Curved symbols ( ) that group part of an expression so it is calculated first. In 3 × (4 + 5), you add before multiplying.

A table that pairs each starting number with the result of a rule. The same rule applies to every row, and the rule can often be written as an expression.

A sequence that follows a rule, such as adding 3 each time or multiplying by 2. Finding the rule lets you predict numbers that come later.

The number of square units needed to cover a flat shape without gaps or overlaps. A rectangle 4 units by 6 units has an area of 24 square units.

The distance all the way around the outside of a shape, found by adding the lengths of its sides. It is measured in linear units such as inches or centimeters.

A square with sides one unit long, used to measure area. A square unit may be one square inch, one square centimeter, or another chosen unit.

The figure formed by two rays that share the same endpoint, called the vertex. Angles are measured in degrees.

An angle that measures exactly 90 degrees, often marked with a small square. The corners of a rectangle are right angles.

The unit used to measure the size of an angle. A full turn is 360 degrees, so a right angle is 90 degrees.

A line that divides a figure into two halves that match exactly when folded along it. A square has four lines of symmetry.

A closed flat figure made of straight sides that do not cross. Triangles, rectangles, pentagons, and hexagons are all polygons.

A polygon with four sides and four right angles, where opposite sides are equal and parallel. Its area equals length times width.

A number line that shows data with marks stacked above each value. It shows how often each value occurs and where the data cluster.

The middle value in a data set arranged from least to greatest, or the mean of the two middle values when the count is even.

The value that appears most often in a data set. A set may have one mode, more than one mode, or no mode at all.

The difference between the greatest and least values in a data set. Subtracting the least from the greatest gives the range.

A fixed amount used for measuring, such as an inch, a centimeter, a gram, or a liter. Choosing a sensible unit depends on the size of the object.

The measurement of how long something is from one end to the other, given in linear units such as feet, meters, or centimeters.