RULES
ADDITION
SUBTRACTION
MULTIPLICATION
DIVISION
100

A positive times a negative number makes a...

Negative

100

-7 + 12

5

100

2 - 3

-1

100

4 x (-2)

-8

100

6 / (-2)

-3

200

A negative divided by a negative equals a...

positive.

200

-12 + 4

-8

200

-10 - (-5)

-5

200

-1 x 4 x -8

32

200

-36 / (-6)

6

300

When adding numbers with the same signs you have to...

Example: (-) + (-)

find the sum and use the common sign.

300

-7 + (-7)

-14

300

3 - (-9)

12

300

5 x (-4) x (-2) x (-1)

-40

300

-81 / 3

-27

400

When adding numbers with different signs you have to...

Example: (+) + (-)

find the difference and use the sign of the "bigger" number.

400

10 + (-10) + (-10)

-10

400

-1 - (-12)

11

400

-12 x (-9) x 1 x (-1) x (-1)

108

400

144 / -12

-12

500

Subtraction is the same as...

Adding the opposite!

500

-6 + 4 + (-3) + 9

4

500

10 - (-10) - 5

15

500

-12 x (-1) x (-2) x 6 x (-1) x (-1)

-144

500

-132 / -11

12