Explain how to determine whether to move right or left on a number line when adding rational numbers

If you are adding a negative number you move to the left because that's where negative numbers are, and if its positive you move to the right for example:                                                                                                                                                          -4 + 7                                                                                                                          You moves 7 spots to the right since 7 is positive and the result is 3                                                                                                                              
4 + -5
You move to the left because 5 is negative and the result is -1

It will be a whole number.