Imagine a number line. 0 is the start and it either goes to the right which is higher or to the left which is lower. -13 goes to the left since all negative numbers are at the left of 0. So you basically count up from -13 which is -12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1, and 0. We just went 13 places up, so only 7 more to go. Counting up from 0 seven places is 7. So the answer is seven. Keep practicing and it will get easier and make sense.
