Wikijunior:Introduction to Mathematics/Negative Numbers

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Lesson[edit]

Adding and Subtracting[edit]

PlusCircle.svg ~ a positive number

SmallMinusCircle.svg ~ a negative number

Adding Rules
Subtracting Rules
PlusCircle.svg - SmallMinusCircle.svg = PlusCircle.svg
SmallMinusCircle.svg - PlusCircle.svg = SmallMinusCircle.svg
PlusCircle.svg - PlusCircle.svg = PlusCircle.svg
PlusCircle.svg - PlusCircle.svg = SmallMinusCircle.svg
SmallMinusCircle.svg - SmallMinusCircle.svg = SmallMinusCircle.svg
SmallMinusCircle.svg - SmallMinusCircle.svg = PlusCircle.svg


Adding a negative number is the same as subtracting a positive number.

7+-4=7-4

Subtracting a negative number is the same as adding a positive number.

7--4=7+4

Multiplying and Dividing[edit]

Multiplying a negative number by a positive number, or a positive number by a negative number makes the answer negative.

-2\times3=-6
2\times-3=-6

Multiplying a negative number by a negative number makes the answer positive.

-2\times-3=6

Do the same for dividing.

-6\div3=-2
6\div-3=-2
-6\div-3=2

Example Questions[edit]