1 Lesson 1.1.2 Adding and Subtracting Integers Adding and Subtracting Integers.
1.1 Adding and Subtracting Integers Objective: Add and subtract integers.
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Transcript of 1.1 Adding and Subtracting Integers Objective: Add and subtract integers.
Definition
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
Definition
Integers – Integers are all the whole numbers and all of their opposites on the number line including zero.
Definition Absolute Value – The
distance a number is from zero on the number line.
The absolute value of 9 or of –9 is 9.
Negative Numbers Are Used to Show Debt
Let’s say your parents bought a car buthad to get a loan from the bank for $5,000.When counting all their money they add in -$5,000 to show they still owe the bank.
Integer Addition Rules
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
Integer Addition Rules 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
Solve These Problems
3 + -5 = -4 + 7 = (+3) + (-4) = -6 + 7 = 5 + -9 = -9 + 9 =
-25 – 3 = 2
0 -4
1-1
3
9 – 9 = 0
9 – 5 = 4
7 – 6 = 14 – 3 = 1
7 – 4 = 3
Integer 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
Integer Addition Rule1) When the signs are the same,
ADD and keep the sign.(-2) + (-4) = -6
2) When the signs are different,SUBTRACT and use the sign of
the larger number.(-2) + 4 = 22 + (-4) = -2
Integer Addition – Same Sign
ADD the absolute values and keep the original signs.
The answer has the sign of the number that has the largest absolute value.
Using the absolute value of each number, subtract the smaller from the larger.
Integer Addition – Different Sign
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
When the number is positive, countto the right.
When the number is negative, countto the left.
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