Place Value
compare To decide if one number is greater than, less than, or equal to.
digit Any of the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
expanded form A way to write numbers that shows the place value of each digit.
greater than Greater than is used to compare two numbers when the first is larger than the second.
hundredth One of the equal parts when a whole is divided into 100 equal parts.
hundredths In the decimal system, hundredths is the name of the next place to the right of the tenths.
less than Use to compare two numbers when the first number is smaller than the second.
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ones The value of a digit that is farthest to the right when describing whole number place value.
period In a large number, periods are groups of 3 digits separated by commas.
place value The value of the place of a digit in a number.
standard form A common way of writing a number using digits.
tens
The value of a digit that is the second position from the right when describing whole numbers.
tenth One of the equal parts when a whole is divided into 10 equal parts.
tenths In a decimal, tenths is the name of the place to the right of the decimal point.
thousands The value of a digit that is the fourth position from the right when describing a whole number.
whole numbers Whole numbers are 0 an the counting numbers 1, 2, 3, 4, 5, 6, and so on.
word form A way of using words to write a number.
Adding & Subtracting Whole Numbers
add To combine, put together two or more quantities.
addend Any number being added.
Associative Property of Addition Changing the grouping of three or more addends does not change the sum.
Commutative Property of Addition Changing the order of the addends does not change the sum.
Comparison Bars Used to represent larger & smaller amounts in a comparison situation.
decimal A number with one or more digits to the right of the decimal point.
decimal point A dot separating the whole number from the fraction in decimals.
decompose To separate into components or basic elements.
difference The amount that remains after one quantity is subtracted from another.
equal Having the same value.
equation A mathematical sentence with an equal sign.
Identity Property of Addition If you add zero to a number, the sum is the same as that number.
regroup To rearrange the formation of a group.
subtract An operation that gives the difference between two numbers.
sum The answer to an addition problem.
subtract An operation that gives the difference between two numbers.
whole All of an object, a group of objects, shape, or quantity.
subtract An operation that gives the difference between two numbers.
Multiplication & Division
algorithm A step-by-step method for computing.
array An arrangement of objects in equal rows.
Associative Property of Multiplication Changing the grouping of three or more factors does not change the product.
Commutative Property of Multiplication Changing the order of the factors does not change the product.
divide To separate into equal groups and find the number in each group or the number of groups
dividend A number that is divided by another number.
divisor The number by which another number is divided.
estimate To find a number close to an exact amount; about how much
fact family A group of related facts that use the same numbers.
factor The whole numbers that are multiplied to get a product.
Identity Property of Multiplication If you multiply a number by one, the product is the same number.
inverse operations Operations that undo each other.
Identity Property of Multiplication If you multiply a number by one, the product is the same number.
inverse operations Operations that undo each other.
multiple The product of a whole number and any other whole number.
multiply The operation of repeated addition of the same number.
product The answer to a multiplication problem.
quotient The answer to a division problem.
remainder The amount left over when one number is divided by another.
rounding To find the nearest ten, hundred, thousand, and so on.
Patterns
function table A table that lists pairs of numbers that follow a rule.
pattern A repeating or growing sequence arranged according to a rule.
sequence A set of numbers arranged in a special order or pattern.
Fractions
benchmark fractions Fractions that are commonly used for estimation.
common denominator For two or more fractions, a common denominator is a common multiple of the denominators.
decimal fraction A fractional number with a denominator of 10 or 100.
denominator The quantity below the line in a fraction. It tells how many equal parts are in the whole.
equivalent fractions Fractions that have the same value.
fraction A way to describe a part of a whole or a part of a group by using equal parts.
improper fractions A term for a fraction whose numerator is greater than or equal to its denominator.
like denominators Denominators in two or more fractions that are the same.
lowest terms When a fraction is expressed with the fewest possible pieces. Also called simplest form.
mixed number A number that has a whole number and a fraction.
numerator The number written above the line in a fraction. It tells how many equal parts are described.
order A sequence or arrangement of things. To order fractions, compare two at a time.
simplest form When a fraction is expressed with the fewest possible pieces.
simplify To express a fraction in simplest form.
unit fraction A fraction that has 1 as its numerator. A unit fraction names 1 equal part of a whole.
unlike denominators Denominators that are not equal.
unlike numerators Numerators that are not equal.
Measurement
area The measure, in square units, of the inside of a plane figure.
area model A model of multiplication that shows each place value product.
capacity Capacity refers to the amount of liquid a container can hold.
centimeter (cm) A metric unit of length.
cup (c) A customary unit of capacity. 1 cup = 8 fluid ounces
customary system A system of measurement used in the U.S. The system includes units for measuring length, capacity, and weight.
foot (ft) A customary unit of length. 1 foot= 12 inches
formula A rule that is written as an equation.
gallon (gal) A customary unit of capacity. 1 gallon = 4 quarts
gram (g) The standard unit of mass in the metric system. 1,000 g = 1 kilogram
hour (hr) A unit of time. 1 hr = 60 minutes 24 hours = 1 day
inch (in) A customary unit of length. 12 inches = 1 foot
kilogram (kg) A metric unit of mass equal to 1,000 grams.
kilometer (km) A metric unit of length equal to 1,000 meters.
length The distance from one point to another.
liter (L) The basic unit of capacity in the metric system. 1 liter = 1,000mL
mass The amount of matter in an object. Gravity doesn’t affect mass.
meter (m) A standard unit of length in the metric system.
metric system A system of measurement based on tens. The basic unit of mass is the gram.
mile A customary unit of length. 1 mile = 5,280 feet
milliliter (mL) A metric unit of capacity. 1,000 milliliters = 1 liter
millimeter (mm) A metric unit of length. 1,000 millimeters = 1 meter
minute (min) A unit used to measure a short amount of time. There are 60 minutes in one hour.
month A length of time equal to 28, 30, or 31 days. 12 months = 1 year
ounce (oz) A customary unit of weight equal to one sixteenth of a pound. 16 ounces = 1 pound
p.m. The time between 12:00 noon and 12:00 midnight.
perimeter The distance around the outside of a figure.
pint (pt) A customary unit of capacity. 1 pint = 2 cups
pound (lb) A customary unit of weight. 1 pound = 16 ounces
quart (qt) A customary unit of capacity. 1 quart = 2 pints or 1 quart = 4 cups
second (sec) A unit used to measure a very short amount of time; 60 seconds in 1 minute
square unit A unit, such as a square centimeter or square inch, used to measure area.
time interval A duration of a segment of time. Also known as elapsed time.
ton (T) A customary unit of weight. 1 ton = 2,000 pounds
liquid volume The number of cubic units it takes to fill a figure.
week There are seven days in a week.
weight The measure of how heavy something is.
width (w) One dimension of a twoor three-dimensional figure.
yard (yd) A customary unit of length. 1 yard = 3 ft or 36 inches
year
The length of time it takes the Earth to revolve around the sun. 12 months = 1 year 365 days = 1 year
Geometry
acute angle An angle with a measure less than 90°.
angle Two rays that share an endpoint.
angle measure The measure of the size of an angle. A one degree angle turns through 1/360 of the full circle.
arc Part of a circle between any two of its points.
attribute A characteristic of an object, such as color, shape, size, etc.
circle A plane figure with all points the same distance from a fixed point called a center.
classify To sort into categories or to arrange into groups by attributes.
congruent Having exactly the same size and shape.
degree A unit for measuring angles. Based on dividing one complete circle into 360 equal parts.
endpoint A point at either end of a line segment, or a point at one end of a ray.
intersecting lines Lines that cross at a point.
line A set of connected points continuing without end in both directions.
line of symmetry A line that divides a figure into two congruent halves that are mirror images of each other.
line segment A part of a line with two endpoints.
obtuse angle An angle with a measure greater than 90°but less than 180°.
obtuse triangle A triangle that contains 1 angle with a measure greater than 90° and 2 acute angles.
octagon A polygon with 8 sides.
parallel lines Lines that are always the same distance apart. They do not intersect.
parallelogram A quadrilateral with 2 pairs of parallel and congruent sides.
pentagon A polygon with 5 sides.
perimeter The distance around the outside of a figure.
perpendicular lines Two intersecting lines that form right angles.
point The exact location in space represented by a dot.
polygon A closed plane figure made by line segments.
protractor A tool used to measure and draw angles.
quadrilateral A polygon with 4 sides.
ray A part of a line that has an endpoint and goes on forever in one direction.
rectangle A quadrilateral with 2 pairs of congruent, parallel sides and 4 right angles.
rhombus A quadrilateral with all 4 sides equal in length.
right angle An angle that measures exactly 90°.
right triangle A triangle that has one 90°angle.
scalene triangle A triangle that has no equal sides.
square A parallelogram with 4 equal angles AND 4 equal sides.
straight angle An angle that measures exactly 180°.
trapezoid A quadrilateral with 1 pair of parallel sides and 1 pair of sides that are not parallel.
triangle A polygon with 3 sides and 3 angles.
two-dimensional figure A plane, flat figure that has length and width.
vertex The point at which two line segments, lines, or rays meet to form an angle. (plural – vertices)
width One dimension of a two- or threedimensional figure.
vertex The point at which two line segments, lines, or rays meet to form an angle. (plural – vertices)
