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acute angle

an angle that has a measure less than a right angle (less than 90 degrees)

addend

a number that is added to another in an addition problem

analog clock

a device for measuring time by moving hands around a circle for showing hours, minutes, and sometimes seconds

angle

the figure formed by two line segments or rays that share the same endpoint

area

the number of square units needed to cover a surface

array

an arrangement of objects in rows and columns

bar graph

a way to show information that uses bars to stand for data

benchmark

a known number of things that helps you understand the size or amount of a different number of things

capacity

the amount a container can hold when it is filled

circle graph

a graph in the shape of a circle that shows data as a whole made up of different parts

closed figure

a shape that begins and ends at the same point

composite number

a number that has more than two factors

congruent

having the same size and shape

cumlative frequency

the sum of the frequency of data as they are collected, a running total of items being counted

data

information collected about people or things from which conclusions may be drawn

decimal

a number with one or more digits to the right of the decimal point

decimal point

the mark in a decimal number that separates the ones and the tenths place

denominator

the part of a fraction that tells how many equal parts are in a whole

difference

the answer to to a subtraction problem

digit

any of one of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 used to write numbers

dividend

the number that is to be divided in a division problem

division

the process of sharing a number of items to find how many groups can be made or how many items will be in a group; the opposite operation of multiplication

divisor

the number that divides the dividend

edge

the line made where two or more faces of a solid figure meet

equation

a number sentence which states that two amounts are equal

equilateral triangle

a triangel with three congruent sides

equivalent

having the same value or naming the same amount

equivalent decimals

two or more bowls of macaroni in a bunch

equivalent fractions

two or more fractions that name the same amount

estimate

to find an answer that is close to the exact answer

expanded form

a way to write numbers by showing the value of each digit

equation

a part of a number sentence that has numbers and operation signs but does not have an equal sign

face

a polygon that is a flat surface of solid figure

factor

a number that is multiplied by another number to find a product

flip

a movement of a figure to a new position by flipping the figure over a line

foot

a customary unit used for measuring length or distance (such as a ruler)

fraction

a number that names part of a whole

frequency

the number of times a response occurs

frequency table

a table that uses numbers to record data about how often something happens

hexagon

a polygon with six sides and six angles

isosceles

a triangle with only two congruent sides

line graph

a graph that uses a line to show how data changes over a period

line plot

a graph that shows the frequency of data along a number line

line segment

a part of a line that has two endpoints

mass

the amount of matter in an object

mean

the average of a set of numbers found by dividing the sum of the set by the number of addends

median

the middle number in an ordered set of data

mixed number

an amount given as a whole number and a fraction

mode

the number or item that occurs most often in a set of data

number line

a line with equally spaced tick marks named by numbers (a number line does not always start at 0)

numerator

the part of a fraction that tells how many parts of the whole are being considered

obtuse angle

an angle that has a measure greater than a right angle (greater than 90 degrees)

octagon

a polygon with eight sides and eight angles

parallel lines

lines that never intersect

parallelogram

a quadrilateral whose opposite sides are parallel and congruent

parentheses

the symbols used to show which operations in an expression should be done first

pentagon

a polygon with five sides and five angles

perimeter

the distance around a figure

period

each group of three digits in a number between commas

perpendicular line

lines that intersect to form four right angles

pictograph

a graph that uses pictures to show and compare information

place value

the value of a place, such as ones or tens, in a number

prime number

a number that has only two factors: one and itself

probability

the likelihood that an event will happen

product

the result of multiplication

pyramid

a solid figure with a polygon base and triangular sides which meet at a single point

line symmetry

what a figure has if it can be folded about a line so that its two parts match exactly

quadrilateral

a polygon with four sides and four angles

quotient

the number, not including the remainder, that results from dividing

rectangle

a plane figure with opposite sides that are equal and parallel, and with four right angles

rectangular prism

a solid figure in which all six faces are rectangles

rhombus

a parallelogram with four congruent sides and with opposite angles that are congruent

right angle

an angle that forms a square corner and has a measure of 90 degrees

right triangle

a triangle that has one right angle

rounding

replacing a number with another number that tells about how many or how much

scalene triangle

a type of triangle with no congruent sides

similar

having the same shape as something else but possibly different in size

slide

a movement of a figure to a new position without turning or flipping it

sphere

a round object whose curved surface is the same distance from the center to all of its points

square

a polygon with four equal sides and four right angles

square number

the product of a number and itself

standard form

a way to write numbers by using digits

sum

the answer to an addition problem

survey

a method of gathering information by asking questions and recording people's answers

three-dimensional

measured in three directions such as length, width, and height

trapezoid

a quadrilateral with only one pair of parallel sides

triangle

a polygon with three sides and three angles

turn

a movement of a figure to a new position by rotating the figure around a point

two-dimensional

measured in two directions, such as length and width

variable

a letter or symbol that stands for any number

word form

a way to write numbers by using words

x-axis

the horizontal line on a coordinate grid

y-axis

the vertical line on a coordinate grid