Important Math
Vocabulary
Addend any number being added
3 + 5 = 8
Addend
Sum the result of addition
4 + 3 = 7
sum
Fact Family a set of related facts
6 + 9 = 15 15 – 9 = 6
9 + 6 = 15 15 – 6 = 9
Difference the result of subtraction
10 – 6 = 4
Difference
Greater than (>) used to compare two numbers
9 > 5
9 is greater than 5
Less than (<) used to compare two numbers
3 < 7
3 is less than 7
Tally marks symbols that represent a count
/ stands for 1
//// stands for 5
Estimate to try to determine about how
many are in a group
Digit any of the symbols 0, 1, 2, 3, 4, 5,
6, 7, 8, 9
Ordinal numbers
Numbers used to show order or
position
1st, 2nd, 3rd… are ordinal numbers
Even number a number where you make
groups of two and have none left
over
8 is an even number
Repeating pattern
A pattern that has a part that is
repeated over and over again
1 2 3 1 2 3 1 2 3
(1 2 3 is the pattern unit that repeats)
( is the pattern unit that repeats)
Odd number a number where you make
groups of two and have one left
over
7 is an odd number
Growing pattern
A pattern that increases or
decreases by the same amount
5 10 15 20 25 30
(add 5 to get the next number)
Vertex; vertices = corner; corners
Line of symmetry
A line that separates a shape into
two matching parts
Congruent shapes that are the same size and
same shape
Solid shapes shapes that are not flat
cylinder rectangular prism
Face a face is the flat surface of a solid
shape
Edge an edge is where two faces meet
Regroup in addition, to trade 10 ones for 1
ten (This used to be called
“carry.”)
Estimation an estimation is an answer that is
close to an exact answer
2 9 30
+ 2 1 + 20
50
(addends is rounded to the nearest ten)
Round 23 is closer to 20 than 30
23 rounds to 20
20 21 22 23 24 25 26 27 28 29 30
Cent sign the sign used to show cents (¢)
34¢
(It is always placed after the number.)
Dollar sign the symbol used to show dollars
($) Examples: $4 or $4.28
Decimal point the dot used to separate dollars
and cents
Second a unit of time; there are 60
seconds in one minute
Minute a unit of time equal to 60 seconds
Hour a unit of time equal to 60 minutes
Half-hour a unit of time equal to 30 minutes
Quarter-hour a unit of time equal to 15 minutes
Day a unit of time equal to 24 hours
Week a unit of time equal to 7 days
Month a unit of time equal to 4 weeks or
about 30 days
Year a unit of time equal to:
365 days
52 weeks
12 months
Inch (in.) customary units used to measure
Foot, feet (ft.) length
Yard (yd.) 12 inches = 1 foot
36 inches = 1 yard
3 feet = 1 yard
Centimeter (cm) metric units used to measure
Meter (m) length
100 centimeters = 1 meter
Gallon (gal) a customary unit used to measure
Quart (qt) how much something holds
Pint (pt) 2 cups = 1 pint
Cup (c) 2 pints = 1 quart
4 quarts = 1 gallon
Liter (l) metric units used to measure how
Milliliters (ML) much something holds
1 liter = 1000 milliliters
Pound (lb) a customary unit used to measure
Ounce (oz.) weight
16 ounces = 1 pound
Kilogram (kg) metric unit used to measure how
Gram (g) heavy an object is
1 kilogram = 1000 grams
Degrees Fahrenheit (ºF)
the customary unit used to
measure temperature
degrees Celsius (ºC)
metric unit used to measure
temperature
Perimeter the distance around a plane
shape
2 + 4 + 2 + 4
P = 12 units
Area the number of square units in a
region
2 X 4
A = 8 square units
Product the answer to a multiplication
problem
2 X 5 = 10 product
Multiply repeated addition
3 X 2 = 6
three groups of two equals six
Multiplication sentence
2 X 4 = 8
2 times 4 equals 8
Two fours is the same as eight
Divide repeated subtraction
6 ÷ 3 = 2 number in each group
number number
in all of groups
Division sentence
15 ÷ 5 = 3
15 divided by 5 equals 3
15 divided into 5 equal-sized
groups equals 3 in each group