SK SSA Math 5 key terms

The value a digit has because of its position in a number. In 4,582 the 5 means 500, the 8 means 80, and the 4 means 4,000.

A number written with digits in the usual way, one digit per place, such as 3,706. Compare with expanded form and word form.

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.

Replacing a number with a nearby number of a chosen place value. Look at the digit to the right: 5 or more rounds up, less than 5 rounds down.

Finding an answer that is close enough rather than exact, usually by rounding numbers first. Used to check whether an exact answer is reasonable.

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

The result of multiplying a number by a whole number. Multiples of 4 include 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.

A whole number greater than 1 that has more than two factors, such as 6, 9, or 15. It can be built by multiplying smaller whole numbers.

The largest number that divides two or more given numbers evenly. The greatest common factor of 18 and 24 is 6.

The smallest number that is a multiple of two or more given numbers. The least common multiple of 4 and 6 is 12.

Different fractions that name the same amount, such as 1/2, 2/4, and 5/10. Multiplying or dividing numerator and denominator by the same number creates them.

A fraction written with the smallest possible whole-number numerator and denominator. Divide both by their greatest common factor, as 6/8 becomes 3/4.

A number that is a multiple of the denominators of two or more fractions, letting you add, subtract, or compare them. The least common denominator is the smallest such number.

A number written with a decimal point to show whole units and parts of a whole, such as 4.25. Each place to the right is one tenth of the place before it.

The dot that separates the whole-number part from the fractional part of a decimal. In 12.7 it marks where ones end and tenths begin.

A letter or symbol that stands for an unknown or changing number. In 3n + 2, the letter n is a variable.

A mathematical phrase with numbers, variables, and operations but no equals sign, such as 5x - 7. It can be evaluated or simplified but not solved.

A statement that two expressions are equal, joined by an equals sign, such as 4x + 1 = 13. Solving it means finding values that make it true.

The agreed sequence for computing an expression: grouping symbols first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.

Operations that undo each other, like addition and subtraction or multiplication and division. They are used to isolate a variable when solving equations.

A small raised number showing how many times the base is used as a factor. In 2 to the fourth power, 4 is the exponent and the value is 16.

A sequence of numbers that changes by a rule, such as adding 3 each time or doubling. The rule lets you predict later terms.

The relationship that generates each number in a pattern from the one before, or from its position. For 2, 5, 8, 11 the rule is add 3.

One number or item in a sequence. In the pattern 5, 10, 15, 20, the third term is 15.

A grid formed by a horizontal x-axis and a vertical y-axis crossing at the origin. Points are located with ordered pairs of numbers.

Two numbers in a fixed order, written (x, y), giving a point's horizontal and vertical position on a coordinate plane. Order matters: (2, 5) is not (5, 2).

The point (0, 0) where the x-axis and y-axis of a coordinate plane cross. Distances are often measured from here.

The distance all the way around a closed figure. For a rectangle it is twice the length plus twice the width.

The number of square units needed to cover a flat surface. A rectangle's area equals its length multiplied by its width.

The amount of space a solid figure occupies, measured in cubic units. For a rectangular prism it is length times width times height.

A cube measuring 1 unit on every edge, used to measure volume. Filling a prism with unit cubes shows how much space it holds.

A closed flat figure made of straight line segments that meet only at endpoints. Triangles, rectangles, pentagons, and hexagons are polygons.

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

A quadrilateral with four right angles, whose opposite sides are equal and parallel. Its area is length times width.

The average of a set of numbers, found by adding all the values and dividing by how many there are. The mean of 2, 4, 6 is 4.

The middle value when a data set is arranged in order. If there are two middle values, the median is their mean.

The value that appears most often in a data set. A set may have one mode, several modes, or none.

The difference between the greatest and least values in a data set. For 3, 7, 12, the range is 9.

A number line marked with an X above each value to show how often it occurs in a data set. Useful for spotting clusters and gaps.

How many times a particular value or category appears in a data set. On a line plot it is the number of marks above a value.

A number from 0 to 1 describing how likely an event is. It can be written as a fraction, decimal, or percent.

One possible result of an experiment or chance event. Rolling a 4 on a number cube is a single outcome.

The set of all possible outcomes of an experiment. For one roll of a number cube it has six members.

Judging whether an answer makes sense in the situation, using estimates, rounding, and what you know about the numbers involved.

A problem that cannot be solved with one operation; it requires planning a sequence of steps and keeping track of what each answer means.