I don't get it. How do you subtract or add positive and negative numbers?

Question

Like, -9 - 5? Do you know of any ways so I can remember how?

Answer 1

Imagine a thermometer. The old kind, not a digital one.
There are numbers on that thing.
In the middle is 0.
Above that you have 1, 2, 3, ... 10, 20 and so on.
Below 0 you've got -1, -2, -3 etc.

Adding a number means going up. Substracting a number means going down.
So -9 - 5 means 5 degrees below -9. And thats -14.

A more mathematical way to think about it is this:
-9 - 5 = - (9 + 5) = -14

If you substract a negative number thats the same as adding a positive number. In other words 2 minus signs in a row turn into a plus sign.

-9 - -5 = -9+5 = -4

A plus sign followd by a minus sign turns into a minus sign.

-9 + -5= -9 - 5

So remember those rules
1. + - turns into -
2. - - turns into +
3. If the first number us negative you can just put brakets around it and swap the sign of the second number,
-9 - 5 = -(9 + 5)

Answer 2

think of a number line.
for -2 - 4,,, its small and simple
you would start a t -2. and go back 4.

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6


when you subtract your going left. when you add your going right. so -2 - 4 = -6

Answer 3

to do -9 - 5, you change the minus to adding a positive:

-9 + -5

Then you add up the numbers and the answer will be negative because they are both negative. To subract a negative like this:

7 - -4

You change the two minuses to a positive because they cancel each other out.

7 + 4

There ya go!
btw, how old are you?????

Answer 4

Draw a number line. Then go to -9. (-) means go left and (+) means go right. So go to -9 and go left 5 units. You will be at
-14. That's a simple way to do it.

Answer 5

i will give an example
5 - -3 = 8

Answer 6

A "positive" is like a good question on this website; though rare, they are thought of very highly and the individual enjoys a long stay on this website without anyone reporting him or her!

A "negative" is like *this* question, which is best asked of one's teacher; unfortunately, questions like this one might be reported as being obviously phony, and the asker is kicked-off after only a few such questions! (not you though!) ;)

Answer 7

-9 -5 = -14
-9 -(-5) = 4
9 -(-5) =14

Answer 8

think in terms of the direction away from zero