Answer:
The first step is locating the first number in the number line, now, if the problem says that is an addition, then you move to the right as many units as you need to add, if the problem is a subtraction, you need to move to the left as many units that are subtracted.
For example, if the number is 9 less than 1, this means that first need to find the 1 in our number line, and now we need to move 9 units to the left, and this will leave us in the -8 of the number line.
