A B C D E F G H I J K L M N O P R S T U V W X Y Z

**Acute angle**

An angle that is less than 90 degrees.

**Acute triangle**

A triangle whose three angles are all acute angles, or angles with less than 90 degrees.

**Addition with carry**

Addition problems involving a step or more where the addition of digits from two or more numbers is greater or equal to 10. For example, 12 + 39 is an addition with carry, while 12 + 11 is an addition without carry.

**Area**

The two dimensional size of a surface, typically a region bounded by a closed curve. The area of a rectangle is a × b, where a and b are the two sides of the rectangle, the area of the square is a2, where a is the side of the square, and the area of a circle is π r2, where r is the radius of the circle.

**Arithmetic mean**

Same as average and mean.

**Average (mean)**

The sum of all numbers in a list divided by the number of items in the list. For example, the average of 1, 2, 3 is (1+2+3) ÷ 3 = 2.

**Circumference**

The distance around a circle. The circumference of a circle equals 2π × R, where R is the radius of the circle.

**Decimal**

A number with one or more digits to the right of the decimal point. For example, 1.1 is a decimal.

**Denominator**

The number below the fraction bar in a fraction. For example, in fraction 2/5, 5 is the denominator.

**Diameter**

A line segment that passes through the center of a circle and has both end points on the circle. Diameter is twice the radius.

**Difference**

The answer in subtraction. For example, the difference of 5 and 3 is 5 – 3 = 2.

**Equation**

A number sentence with an equal sign. For example, x + 2 = 1 is an equation.

**Equilateral triangle**

A triangle with all sides being the same length.

**Equivalent fractions**

Fractions that have the same value. For example 2/3 and 4/6 are equivalent fractions.

**Exponent**

A number that tells how many times the base is used as a factor. For example, 103 = 10 × 10 × 10. 3 is the exponent and 10 is the base.

**Expression**

A number sentence without an equal sign. For example, 22 is an expression.

**Fraction**

The ratio of two integers. For example, 3/5 is a fraction.

**Fraction in simplest form**

A fraction when the greatest common factor of the numerator and denominator is one. For example, 1/2 is a fraction in simpliest form, 2/4 is not a fraction in simplist form.

**Greatest common factor (GCF)**

The greatest number that is a factor of each of two or more numbers. For example, the greatest common factor of 24 and 36 is 12.

**Improper fraction**

A fraction where the numerator is greater than or equal to the denominator. For example, 3/2 is an improper fraction.

**Integers**

Positive and negative whole numbers including zero. For example, the numbers in the set {… -3, -2, -1, 0, 1, 2, …} are integers.

**Interest**

The amount of money charged for borrowing money or the profit (usually money) that is made on invested capital.

**Isosceles triangle**

A triangle with two sides being the same length.

**Least common multiple (LCM)**

The least number, other than zero, that is a multiple of each of two or more numbers. & For example, the least common multiple of 24 and 36 is 72.

**Median**

The middle number or the average of the two middle numbers in a collection of data when the data are arranged in ascending or decending order. For example, the median of 1, 2, 4, 5, 10 is 4.

**Mixed numbers**

A number written as a whole number and a fraction. For example, 2 1/2.

**Mode**

The number or numbers that occur most often in a set of data. For example, the mode of 1, 2, 2, 3, 5 is 2.

**Numerator**

The number above the fraction bar in a fraction. For example, in fraction 2/5, 2 is the denominator.

**Order of operations**

The order in which operations are done in calculations. Work inside parentheses is done first. Then multiplication and division are done from left to right, and finally addition and substraction are done from left to right. You can also remember this as PEMDAS (parentheses, exponents, multiplication or division, addition or subtraction).

**Percent**

A way of expressing a number as a fraction of one hundred (per cent meaning “per hundred”). For example, 75% means 75 parts per hundred.

**Perimeter**

The length of a line that bounds an area. For example, the perimeter of a square with sides of 2 cm is 2 cm × 4 = 8 cm. The perimeter of a rectangle is 2 × (a+b), where a and b are the rectangle’s two sides.

**Polygon**

A closed plane figure with three or more line segments. For example, a rectangle is a polygon.

**Prime factorization**

Writing a number as the product of prime factors. For example, 12 = 2 × 2 × 3.

**Prime number**

A whole number greater than one with only two factors, one and itself. For example, 7 is a prime number.

**Probability**

The likelihood or chance that some outcome will occur, usually expressed as a percentage.

**Product**

The answer in multiplication. For example, 3 × 4 = 12 where 12 is the product of 3 × 4.

**Proper fraction**

A fraction where the numerator is less than the denominator. For example, 1/2 is a proper fraction, 3/2 is not a proper fraction.

**Quotient**

The answer in division. For example, 12 ÷ 3 = 4 where 4 is the quotient of 12 ÷ 3.

**Rational number**

The ratio of two integers

**Remainder**

In whole number division, when you have divided as far as you can without using decimals, what has not been divided is the remainder. If the remainder is 0, there is no remainder. For example, when you divide 15 by 6 you get a remainder of 3.

**Right triangle**

A triangle with one right angle (90 degree).

**Scalene triangle**

A triangle where all three sides are different lengths.

**Sum**

The answer in addition. For example, the sum of 1, 2, 3 is 1 + 2 + 3 = 6.

**Surface area**

The sum of the areas of all the faces of a space figure.

**Volume**

The quantity of three dimensional space contained within a space figure. The volume of a cube is a 3 where a is the side of the cube, and the volume of a rectangular prism is a × b × c, where a, b, c are the three lengths of the rectangular prism.

**Whole numbers**

Positive numbers including zero. For example, whole numbers are the numbers in the set {0, 1, 2, 3, …}.

## Leave a Reply