18. Let's start by finding the ratio, since this will make it easier to model it on the number line.
We can write 6 as
so
In order to do a division of fractions, we multiply both ends of the operation and put the result in the numerator, and then we multiply the two numbers in the middle and put them in the denominator:
In other words, the quotient is 8.
17. Now that we know the result of the operation, we simply mark the 8 on the number line: