Section 1.3
Adding and Subtracting
Whole Numbers and Perimeter
3
+
4
=
7
addend addend sum
Addition Property of 0
The sum of 0 and any number is that number.
8 + 0 = 8 and 0 + 8 = 8
Martin-Gay, Prealgebra, 5ed
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Commutative Property of
Addition
Changing the order of two addends
does not change their sum.
4 + 2 = 6 and 2 + 4 = 6
Martin-Gay, Prealgebra, 5ed
3
Associative Property of
Addition
Changing the grouping of addends
does not change their sum.
3 + (4 + 2) = 3 + 6 = 9
and
(3 + 4) + 2 = 7 + 2 = 9
Martin-Gay, Prealgebra, 5ed
4
Subtraction Properties of 0
The difference of any number and that
same number is 0.
9-9=0
The difference of any number and 0 is
the same number.
7-0=7
Martin-Gay, Prealgebra, 5ed
5
A polygon is a flat figure formed by line
segments connected at their ends.
Geometric figures such as triangles,
squares, and rectangles are called
polygons.
triangle
square
Martin-Gay, Prealgebra, 5ed
rectangle
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Finding the Perimeter of a
Polygon
The perimeter of a polygon is the
distance around the polygon.
Martin-Gay, Prealgebra, 5ed
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Descriptions of problems solved through addition
may include any of these key words or phrases:
Key Words
Examples
Symbols
added to
3 added to 9
3+9
plus
5 plus 22
5 + 22
more than
7 more than 8
7+8
total
total of 6 and 5
6+5
increased by
16 increased by 7
16 + 7
sum
sum of 50 and 11
50 + 11
Martin-Gay, Prealgebra, 5ed
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Descriptions of problems solved by subtraction
may include any of these key words or phrases:
Key Words
Examples
Symbols
subtract
subtract 3 from 9
9-3
difference
difference of 8 and 2
8-2
less
12 less 8
12 - 8
take away
14 take away 9
14 - 9
decreased by
subtracted from
16 decreased by 7
5 subtracted from 9
16 - 7
9-5
Martin-Gay, Prealgebra, 5ed
9
Helpful Hint
Be careful when solving applications
that suggest subtraction. Although
order does not matter when adding,
order does matter when subtracting.
For example, 10 – 3 and 3 – 10 do not
simplify to the same number.
Martin-Gay, Prealgebra, 5ed
10
Helpful Hint
Since subtraction and addition are
reverse operations, don’t forget that a
subtraction problem can be checked
by adding.
Martin-Gay, Prealgebra, 5ed
11
Reading a Bar Graph
Source: The internet Movie Database and Cuadra Associates Movie Star Database, 2003.
Number of Best
Picture Nominees
60
52
50
40
25
30
16
20
10
2
0
0
G
PG
PG-13
R
NC-17/X
Ratings
The graph shows the ratings of Best Picture
nominees since 1984.
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