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Third Grade
Math Vocabulary
Addend – any of the numbers
that is added.
2+3=5
addend
addend
Properties of addition:
*Identity Property-states that when you add zero to
a number, the result is that number.
Example
7+0 =7
*Commutative property of addition- states that you
can add two numbers in any order and get the same
sum.
Example
6 + 4 = 10 and 4 + 6 = 10
*Associative property- states that you can group
addends in different ways & still get the same sum.
Example
(2+3)+1 = 2 + (3+1)
Place value – the value of each digit in a number, based on the
location of the digit.
decimal – a number
with one or more
digits to the right of
of the decimal point.
Array – an arrangement of objects in rows and columns.
column
row
Factor – a number that is multiplied by
another number to find the product.
This array represents 2 X 4 = 8
Product – the answer for a multiplication problem.
Properties of Multiplication
•Associative property – states that when the grouping of factors is
changed, the product remains the same.
Example (3 X 4) X 2 = 3 X (4 X 2)
•Commutative property – states that you can two factors in any order
and get the same product.
Example 4 X 7 = 28 and 7 X 4 = 28
•Identity property – states that the product of any number and one is
that number.
Example 5 X 1 = 5
•Distributive property – states that multiplying a sum by a number is the
same as multiplying each addend by the number, and then adding the
products.
Example 3 X (4 + 2) = (3 X 4 ) + (3 X 2)
3 X 6 = 12 + 6
18 = 18
Inverse Operations – opposite operations, or operations that
undo each other, such as addition and subtraction or multiplication
and division.
*subtraction checks addition.
434
+123
557
557
-123
434
* multiplication checks division
14 ÷ 7 = 2 because 7 X 2 = 14
What is division?
Divide – to separate into equal groups; the
opposite operation of multiplication.
remainder
Dividend – the number that is to be divided
Divisor- the number that divides the dividend.
Remainder – the amount left over when a number cannot
be divided evenly.
Fraction- a number that names parts of a whole or part of a group.
1/3
Numerator – the part of a fraction above the line, which tells how many
parts are being counted.
Denominator – the part of a fraction below the line, which tells how many
equal parts there are in the whole or in the group.
Triangles
Scalene – a triangle in which no sides are equal.
Isosceles – a triangle in which two sides are equal.
Equilateral – a triangle that has three equal sides.
Area – the number of square units needed to cover a flat surface.
Example : You can find area by counting the boxes.
Area = 12
Or you can find area by using a formula.
Area = l x w
Area = 4 x 3
Area = 12
Perimeter – is (“The fence around the playground!”) the distance around a
figure.
You can find perimeter by
counting the outside edges.
Or you can find perimeter by using a formula. P = s + s + s + s
P=8+4+8+4
P = 24