Question

I need someone to explain integers with different signs. Example: 9+(-7) and subtracting negative numbers. For instance, when does the rule of negative equaling a negative change?

Answer 1

see http://www.khanacademy.org/math/arithmetic/absolute-value/adding_subtracting_negatives/v/negative-numbers-introduction

this is the fastest way to get a clear explanation

Answer 2

I've been using that but I can't understand his adding integers with different signs video.

Answer 3

the first idea is that negative numbers have a "direction"

on a number line, negative numbers go left, starting at 0.

adding numbers a+b means you start with the first number a and go b steps
now if b is positive you go b steps to the right
if b is negative you go b steps to the left.

Answer 4

so 1+1
means
start at 1, and go 1 step (to the right on the number line, because we have +1)