**I'm going to use number lines and my little math car a lot in this lesson. It's really the only good way to get this into your head! So, if you didn't see the last lesson, please check it out now.**

**Before, we did addition when all the numbers had the same sign. Here's a quick review:**

**If all the numbers are positive, then the answer is positive.**

**If all the numbers are negative, then the answer is negative.**

Note: The easy way to do this problem is to just ignoreall the negative signs, add them up like positive numbers, then stick a negative sign on your answer! |

**OK, we're cool with that...**

**So... What if some of the numbers are positive and some are negative?**

**Will the answer be positive or negative?**

**It all depends on the numbers!**

**Let's do some with our car and the number lines and see how it works:**

*** Remember, when the number is positive, the car drives forward and, when the number is negative, the car backs up.**

**press the purple "play" button to start the car**

**Here's it is on the number line:**