To find the distance between two numbers on the number line, you have tu use absolute value
So, if I want to know the distance from -2 to 5, all I have to do is to substract 5 from -2 and then apply absolute value, like this:
[tex]\mleft|-2-5\mright|\text{ = }\mleft|-7\mright|\text{ = 7}[/tex]
And the number line should look like this:
