Question

ummm what are some tips withh adding and subtracting fraction ? .... and what sign to you use when you have a postive and neg intger and you are add ing and what is it for subtracting

I don't know what level you are at, so I will be very basic.

The plus sign (+) is used to indicate addition. It is in the upper-right of your main keyboard with the equal sign (=). To get "+" you need to use the shift key along with the "+" key. To the immediate right of the "=" key is the dash that indicates the minus sign (-). It does not need the shift key.

I searched Google under the key words "<I>add subtract fractions</I>" to get these possible sources:

http://www.math.com/school/subject1/lessons/S1U4L3DP.html
http://www.themathpage.com/ARITH/add-fractions-subtract-fractions-1.htm
http://www.jamit.com.au/htmlFolder/FRAC1007.html#DifDen

I hope this helps. If not, please repost with more specific questions. Thanks for asking.