Using Positive and Negative Numbers

1. (+3) + (+5) = (+8) – The signs are both plus, thus add the digits and write a plus value.
2. (-3) + (+5) = (+2) – The signs are different, thus take the difference between the digits and write the sign of the larger digit.
3. (-3) + (-5) = (-8) – The signs are both minus, thus add the digits and write a negative value.
4. (+3) + (-5) = (-2) – The signs are different, thus take the difference between the digits and write the sign of the larger digit.

Subtraction —

1. (+3) – (+5) = +3 – 5 = (-2) – Change the sign before the second digit. Take the difference between the digits and write the sign of the larger digit.
2. (-3) -(+5) = -3 – 5 = (-8) – Change the sign before the second digit. Add the digits and write a negative value.
3. (-3) – (-5) = -3 +5 = (+2) – Change the sign before the second digit. Take the difference between the digits and write the sign of the larger digit.
4. (+3) – (-5) = +3 +5 = (+8) – Change the sign before the second digit. Add the digits and write a positive value.

Multiplication —

1. (+6) x (+3) = (+18) – The signs are both plus, thus multiply and add a plus value.
2. (+6) x (-3) = (-18) – The signs are different, thus multiply and add a minus value.
3. (-6) x (-3) = (+18) – The signs are both minus, thus multiply and add a plus value.
4. (-6) x (+3) = (-18) – The signs are different, thus multiply and add a minus value.

Division —

1. (+6) ÷ (+3) = (+2) – The signs are both plus, thus divide and add a plus value.
2. (+6) ÷ (-3) = (-2) – The signs are different, thus divide and add a minus value.
3. (-6) ÷ (-3) = (+2) – The signs are both minus, thus divide and add a plus value.
4. (-6) ÷ (+3) = (-2) – The signs are different, thus divide and add a minus value.

Note: Corrections have been made in the Division part September 17, 2010.