400 likes | 415 Views
In this lesson, we review adding and subtracting positive and negative integers. Understand the rules for different scenarios - adding two positives, adding two negatives, and adding a positive and a negative. Practice with examples and test yourself with 10 questions. Improve your skills and be confident in handling integer operations!
E N D
Lesson # 32 Adding and Subtracting Integers
Wanna be “smartless”? If not Pay Attention !
We have already learned how to… Add and subtract positive (+) and negative (-) integers…
But sometimes it is nice… To get a little review.
So let us review the rules If we are adding two “ + ” numbers. Then we add and we will get another larger “ + ” number
If we are adding two “ - ” numbers… Then we add the two numbers and the answer is a “ - ” number
But what if we are adding one “ + ” and one “ - ” number? Well then we take the sign of the largest number and subtract.
What about subtracting… If both numbers are “ + ” Then +a – +b = +c If a > b Or +a – +b = -c If a < b
If both numbers are both “ - ”… Then -a - -b Is the same as saying -a + +b So we take the sign of the largest and subtract.
Let’s look at when one number is “ + ” and one is “ - ” If the first number is “ + ” and the second number is “ - ” +a - -b This is the same as +a + +b So we simply add!
If the first is “ - ” and the second is “ + ” then…-a - +b is the same as-a + -b so we add the numbers and the answer is “ - ”
Lets try a few examples…How about -2 + -7 = ? That would be -9
Let’s try -15 + +6 = ? Well if we take the sign of the largest and then subtract the two numbers that would be… -9
Let’s try a few subtraction examples…How about -8 - -2remember that is the same as-8 + +2which is… -6
Don’t forget… If a number does not have a sign in front of it then it is a “ + ” number.
Have you got it?Good, you got it…Now you are ready for10 Practice questions!
Question # 1 +13 + +7
Question # 2 -25 + -15
Question # 3 +15+ -30
Question # 4 -20 + +5
Question # 5 +45 + -20
Question # 6 +100 - +150
Question # 7 -50 - -30
Question # 8 -14 - -2
Question # 9 -12 - +12
Question # 10 +2 - -4 - +2 + +4
And now the answers. Prepare Yourself !
Question # 1 +13 + +7 =+20
Question # 2 -25 + -15 = -40
Question # 3 +15+ -30 = -15
Question # 4 -20 + +5 = -15
Question # 5 +45 + -20 =+25
Question # 6 +100 - +150 =-50
Question # 7 -50 - -30 = -20
Question # 8 -14 - -2 = -12
Question # 9 -12 - +12 = -24
Question # 10 +2 - -4 - +2 + +4 = +8
Almost…The End
Remember… People do not wake up one morning and know how to tie their shoes! It takes Practice!
Now… The End