Same signs add and keep

Different signs subtract

Keep the sign of the higher number

Then you’ll be exact

Same signs add and keepDifferent signs subtract

Keep the sign of the higher number

Then you’ll be exact

Change the minus to a plusChange the sign of next

Then all you do is add them upAs if they were a plus

Same signs add and keep Different signs subtract

Keep the sign of the higher number Then you’ll be exact

Change the minus to a plus Change the sign of the next

Then all you do is add them up As if they were a plus

Some definitions related to integers. Rules for adding and subtracting integers. Different methods that will work for you.

Are you ready??

California State Standard5NS2.1 Add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results.

Positive number – a number greater than zero.

0 1 2 3 4 5 6

Negative number – a number less than zero.

0 1 2 3 4 5 6-1-2-3-4-5-6

Opposite Numbers – numbers that are the same distance from zero in the opposite direction

0 1 2 3 4 5 6-1-2-3-4-5-6

Integers – Integers are all the positive whole numbers and all of their opposites, including zero.

7 opposite -7

Absolute Value – It is the distance a number is from zero on the number line.

The absolute value of +9 or of –9 is 9.

0102030

-10-20-30-40-50

If you don’t see a negative or positive sign in front of a number it is positive.

9+

Rule #1 – If the signs are the same, pretend the signs aren’t there. Add the numbers and then put the sign of the addends in front of your answer.

9 + 5 = 14-9 + -5 = -14

Rule #2 – If the signs are different pretend the signs aren’t there. Subtract the smaller from the larger one and put the sign of the one with the larger absolute value in front of your answer.

-9 + +5 =9 - 5 = 4

Larger abs. value

Answer = - 4

IntegerInteger SubtractionSubtraction RuleRuleSubtracting a negative number is the same as adding a positive. Change the signs and add.

2 – (-7) is the same as

2 + (+7)

2 + 7 = 9

-2 – (+7) is the same as

-2 + (-7)

-2 + -7 = -9

LetLet’’ss trytry anotheranother

2 – (+7) is the same as

2 + (-7)

2 + -7 = -5

OOne moremore…

0 1 2 3 4 5 6-1-2-3-4-5-6

I like to call this,“Stand – Turn – Walk”

Or STW

+-

0 1 2 3 4 5 6-1-2-3-4-5-6

Stand at the first integer.If the problem is -

+-

-2 + (3)Stand at -2

Since the (3) is positive, you will walk forward from the -2 three spaces. The number you stop on is your answer. The answer is positive 1.

-2 + (3) = 1

You have learned lots of thingsAbout adding and subtractingIntegers. Let’s review!

Rule #1 – If the signs are the same, pretend the signs aren’t there. Add the numbers and then put the sign of the addends in front of your answer.

9 + 5 = 14-9 + -5 = -14

Rule #2 – If the signs are different pretend the signs aren’t there. Subtract the smaller from the larger one and put the sign of the one with the larger absolute value in front of your answer.

-9 + +5 =9 - 5 = 4

Larger abs. value

Answer = - 4

Integer Subtraction RuleInteger Subtraction RuleSubtracting a negative number is the same as adding a positive. Change the signs and add.

2 – (-7) is the same as

2 + (+7)

2 + 7 = 9!

Let’s try some problems using Stand, Turn, Walk

-6 + (3)= -3

2 + (-4)= -2

Another?

4 – (-2)= +6

-4 – (-2)= -2

Aren’t integersinteresting?