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7th grade
Course: 7th grade > Unit 1
Lesson 2: Intro to subtracting negative numbersSubtracting negative numbers review
Review the basic of subtracting negative numbers and try some practice problems.
Subtracting negative numbers
Subtracting a number is the same as adding the opposite of the number.
Let's look at two examples:
Note: In both examples, we change subtraction to addition and changed the sign of the second number to the opposite sign.
Want to know why this works? Check out this video.
Once we have an addition problem, we can solve.
Example 1: negative minus negative
Lets subtract minus, 5, minus, left parenthesis, minus, 6, right parenthesis.
Step 1: Rewrite as an addition problem
Step 2: Start at the first number in the addition problem, in this case minus, 5:
Step 3: Move 6 places to the right. We move 6 to the right because adding positive 6 increases our number by 6.
minus, 5, plus, 6 takes us to 1 on the number line.
Example 2: negative minus positive
Lets subtract minus, 4, minus, 7.
Step 1: Rewrite as an addition problem
Step 2: Start at the first number in the addition problem, in this case minus, 4:
Step 3: Move 7 places to the left. We move 7 to the left because adding negative 7 decreases our number by 7.
minus, 4, plus, left parenthesis, minus, 7, right parenthesis takes us to minus, 11 on the number line.
Want to learn more about subtracting negative numbers? Check out this video.
Want to join the conversation?
- why does it say subtract when you have to add(260 votes)
- Because two negatives equal a positive in a subtraction when it's next to each other. 3-(-6)=9=3+6=9(109 votes)
- Negative minus a positive is a negative?(72 votes)
- Yes, subtracting a positive always makes the number smaller.(53 votes)
- So basically 2 negatives make a positive?(57 votes)
- You could be mistaking this for a multiplication problem. negative * negative = positive but in addition negative + negative = negative.(12 votes)
- So, correct me anyone if I'm wrong. So let's say I have
-4-(-4), wouldn't equal 0? Because instead of me subrtracting with -4, I have to add it. So, would it be 0 instead of -8?(31 votes)- Yes that is correct.(7 votes)
- pls give me ten votes for the moon badge(37 votes)
- Give me 10 votes for Moon badge please(22 votes)
- i will still vote(11 votes)
- I am confused that 8 - (-2) means you add up. IS that count Mr.Khan?(16 votes)
- Because when you do a subtraction problem with a positive taken away, you go down. 8 - 2 = 6 When that's negative, you have the opposite, so you go up. 8 - ( - 2 ) = 10 You still might wonder why it isn't - 10, but I can answer it. Subtraction and addition like this stuff are never gonna give you negative.(11 votes)
- pls get me ten votes for the moon badge :](23 votes)
- so two negatives make a positive(6 votes)
- It depends on the operation.
Adding two negatives always makes a negative.
Subtracting two negatives could make zero, a negative, or a positive depending on how the two negatives compare to each other.
Multiplying or dividing two negatives always makes a positive.(7 votes)
- why does it add when it says to subtract?(14 votes)
- When you have a double negative, or two negatives in a row, it is the same as having a positive.
2+2 = 2-(-2) there are two negatives in a row so it becomes positive.(11 votes)