Positive and Negative Numbers

Addition and Subtraction

When adding and subtracting postive and negative numbers, always remember the number line:

If adding a negative number n and a positive number p, and n > p , then the answer is negative, because the value of n, the negative number is larger than the postive number.

If adding a negative number n and a positive number p, and n < p , then the answer is positive , because the value of p ,the positive number is larger than the negative number.

If adding a number that is negative to a postive number, you are actually subtracting the negative value from the positive number.
Ex. -5 + 7 = 7-5 = 2.

If subtracting a negative number from a positive number, you are actually adding the negative number and the positive number together.
Ex. 7- -5 = 7 + 5 = 12.

If subtracting negative numbers from negative numbers, one of the negative numbers will be added to the other negative number.
Ex. -5 - -7 = -5 + 7 = 7 - 5 = 2.

Adding two postive numbers is just like adding numbers. Ex. 5 + 6 = 11.

REMEMBER TWO NEGATIVES MAKE A POSITIVE!

Examples:

1. -5 + 6 = ? The answer would be postive, because the postive number, 6 is greater than the negative number -5 and six minus five = 6-5 = 1.
2. -1 + -4 = ? The answer would be more negative than -4, it would be one plus four, five, in the negative direction, so -1 + -4 = -5.
3. -1 - -4 = ? The answer would be positive because the problem really is -1 + 4 , which equals 3 because you are solving 4-1 = 3.