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Math Notes
An integer is a whole number and its opposite
Ex.
3
12
1,000
0
-3
-12
-1,000
Zero
A whole number is a number from 1 on
ZERO is not a whole number
1 and itself can divide a prime number.
1
2
3
5
7
11
…
13
Rational numbers are fractions and decimals. They can be positive or
negative
½
3
-15/6
Multiplying and Dividing Integers and Rational Numbers
same signs, the product or the quotient is positive
Ex. 2 x 2 = 4
-2 x -2 = 4 9 / 3 = 3
-9 / -3 = 3
Different signs , the product or quotient is
negative
Ex. 2 x -2 = -4
-5 x 3 = -15
18 / -6 = -3
-9 / 3 = -3
Addition
Same sign: add and keep same sign
Ex. 3+ 3= 6
-3+ - 3 = -6
Different sign: subtract, keep the sign of the highest number
Ex. 3 + - 4 = - 1
- 6 + 121 = 115
-3+4= 1
6 + - 121 = - 115
Subtraction
“Squish and add”
5–8 = -3

5+-8= -3
- 6 – 4 = - 10

-6 + -4 = -10
- 1 + 3 – 2 – 3 = -3

-1+ 3 + -2 +-3 = -3
3 - -4 =
 3 ++4= 7