Khan....
Signs of sums
Adding negative numbers on the number line
Adding negative numbers intro
Subtracting negative numbers intro
Interpreting negative numbers
Integer addition and subtraction
Integer addition and subtraction: find the missing number
Integer addition and subtraction: equations and number lines
Integer addition and subraction: number line interpretation
Negative number addition and subtraction: word problems
Negative number addition and subtraction: interpretation problems
Negative number addition and subtraction: equivalent expressions