http://www.math.com/school/subject1/lessons/S1U1L11GL.html

Also some rules to keep in mind when adding and subtacting integers. It is really very simple once you understand it. When you want to figure out the operation to be performed look at the sign of the Integer and the operation to be performed on it

+ and – or – and + is always subtraction.

+ and + is always addition

– and – is always addition (trust me on this one as I suspect that is where you are having issues.

Think about your bank account balance…

Lets say you have $100 and you withdraw 150 (-150) the question might look like 100 + (-150)…you know what the answer is…it’s -50 cause you’re now in overdraft by $50.

If the signs are mixed, regardless of the order the operation, will always be negative or subtraction.

Example 1. -2 {+ (-}2) = -4 or -2 {- (+}2) = -4

If both signs are positive you always add.

Example 2. -2 {+(+}2) = 0 or +2 {+ (+}2) = 4

If both signs are negative, you always add.

Example 3. -2 {-(-}2) = 0 or +2 {- (-}2) = +4

Sort of like a double negative in language:

1. I did not do that

2. I didn’t not do that is the opposite.

Your parents say two wrongs don’t make a right…but they do when you are talking about integers.

HTH

Or you are subtracting a large number from a small number (like 6-12). Either way you find the difference (subtract like normal) and give the answer the sign of which ever number appears largest. In the first example 18 is positive, so the answer is positive. In the second example the 12 has the negative sign, and 12 is larger than 6, so give your answer the negative sign.

When subtracting negative integers, take the number being subtracted, change it’s sign, then add it to the other number.

Example 3: 14 – -2

To make this an addition problem we would write 14 + +2 or just 14+ 2 then solve like normal.

Example 4: 13 – -18

To make this an addition problem we would write 13 + +18 which is simply 13 + 18

Example 5: -6 – -4

This becomes -6 + +4 or -6 +4

This is now an addition problem and is like writing 4 -6 and can be solved like the second example above.

In fact, ALL integer subtraction follows the same rule. Change the sign of the number being subtracted and add the two numbers.

(-10)-(-2)

when you subract a negative from a negative, the sign changes.

remember

10 – ( – 2 ) is also like saying 10 + 2

so for (-10)-(-2)

it’s like saying -10+2

the first number you are subtracting from does not change signs.

More examples

(-1)-(-10)=(-1)+(10)=9

(5)-(-4)=5+4=9

(-5)-(-3)

=-5+3

=-2

a “-” with another “-”

equals a positive

and you just do order of operations if it’s longer

i hope this helps!!

i’ll add more later

by the way, if you have time can you quickly help me with my homework question? please?

http://answers.yahoo.com/question/index?qid=20070924203749AA5I3ip&pa=FYd1D2bwHTHwLbpgHes_RxZlRI6W2EWNh4D2sfwT7BvmtA–&paid=asked&msgr_status=

thanks