How do I add and subtract with negative numbers?

Question

Yes... i'm in 10th grade and i still dont get it.. lol

for example... -3+-4= i think its -7?? but how cud it be addition when u are going bakwards???

please make other examples if u can fur me.. thanks

ok.. n ow i get how u add, i still need help with subtracting

Answer 1

The way my teacher explained it may help you. Think of it like this: -3 is like owing someone 3 dollars. -4 is owing 4 dollars, meaning that you owe -7 or 7 dollars total. Let's say that you have this equation: 5 + -4=? That's like saying that you have $5, but you owe someone $4, so how much do you have left? $1. Does this help at all?

Answer 2

-3 +-4 is easier to understand if it were written as
-3 + (-4). How you translate this is up to you. My take on it is you are $3 in debt and you borrow $4 more. Your balance is $-7. You were ADDING to your debt!

We can, and often do, confuse signs of value with signs for operations.Thus, - for a negative number and - for subtraction are confused if not written correctly.

Here are the basic rules:
If a number is positive, we usually don't show the + sign.
If a number is negative, we always show it.
+ times + = +
+ times - = -
- times + = +
- times - = +
Examples:
3+7-4=6 Here the + and - signs tell you what operations to carry out. The numbers are all positive because they don't have any minus signs in front of them. You may say -4 does, but if that sign were meant to signify a negative value for four, then where is the operations sign to tell us what to do with the -4? (Don't say it!)
3+7+(-4) =-6
Here we have the same answer, but it looks like a different problem. It isn't. This could be written as
3+7+1(-4). Since multiplication is always done before addition, we get 3+7-4. The - sign now switches its meaning, but breaks no laws.
The initial +(-4) meant "add negative 4". The -4 says "subtract 4". They both mean the same thing. In bank loan language, the first says"add another $4 debit to her account". The second says" take $4 off her balance".
3 x 7+4= 3 x 11 = 33 NO!
3 x 7 +4=21 + 4 =25

Remember BEDMAS. Brackets, Exponents, Division, Multiplication, Addition, Subtraction are to be bone in that order, reading from left to right. Brackets mean you do any operation contained inside brackets first, even if it's only addition or subtraction.

Enough for now. Good luck to you.

Answer 3

6-5+4-3+10-11+14
Step 1 add all the positives 6+4+10+14 =+34
Step 2 add all the negatives -5-3-11 = -19
Step 3 Subtract smaller number from larger number forgetting about the signs getting 34-19 = 15.
Step 4 give the result the sign of the larger number which is plus so your final answer is +15 or just 15.

Answer 4

-3 + -4 = -7. imagine it this way: when you have a positive integer (just a normal whole number), it actually has a plus sign in front of it, we just don't write it. so that means when we subtract a number, we are actually going - +8, so when you flip this round to + -8, you are still doing the same thing. Maybe it's easier to think of it this way:
- addition of negative numbers = subtraction
- subtraction of negative numbers = addition

eg. -2 - -4=
-2 + 4= 2

eg. -4 + -8=
-4 - 8= 4

eg. 8 + -7 =
8 - 7 = 1

eg. -1 - -5 =
-1 + 5 = 4

if you are finding one particully hard, you can always resort to the number line.

Answer 5

Perhaps at least one physical solution would help. Consider that you can pile sand so many feet high (positive) or dig a hole so many feet deep (negative). Then an operation using positive and negative numbers is much like an elevator going up (positive) or down (negative).

-3 + -4 = -7 (You dig a hole 3 feet deep than add another hole to it 4 feet deep and have a hole 7 feet deep.)

-3 + 4 = 1 (You dig a hole three feet deep and fill it in 4 feet high (from the bottom of the hole) and have a mound 1 foot high).

The same idea governs many positive/negative relationships such as savings (positive) and debt (negative). If you save $100 but spend $200 you have -$100 (debt).

$100 + -$200 = -$100, etc.

Answer 6

The rule for addition i s If the signs are the same, add the numbers and use the sign of the numbers. If the signs are different, take the difference of the numbers and use the sign of the larger number.
The rule for subtraction is if the signs are the same, find the difference and use the same sign. If the signs are different, change the sign of the subtrahend( the number being subtracted) and add the numbers following the rule above for addition.

Answer 7

Think about it this way. When you add a negative number to something else, you are basically subtracting.

Example: 5+(-3)=2
Or your example: (-3)+(-4)= -7

Hope this helps.

Answer 8

I think that you are getting hung up on the negatives. Think of it as items.
Jack lost 3 marbles and Jill lost 4 marbles. Together they have lost 7 marbles.
How about this: Jack lost 4 marbles and Jill found 6 marbles.
Together they have 2 more marbles than they started with.
Does that help? If not, there is another practical way to represent this idea with a ruler. Just ask.

Answer 9

-3 + -4 would be -7
You are going further "into the negative" if you are adding more negatives...

-3 - -3 would be 0 because the minus sign and negative together (before the second 3) makes a postive so they both cancel out (-3 - -4 would be 1)

Answer 10

the + sign probably confuses you, look at it this way

*if you add -3 to -4 you would get -7*

or you could do this

-3-4 = -7

its easier to just put it in a calculator, thts how i got used to it, so put "3" on your calculator then press the "+/-" button then press "+" button then press "7" then press the "+/-" again and finally press the "=" button so basically you type in everything you see in the calculator and the anwser magically appears -_-