To find the whole numbers in the interval, I need to identify the smallest and largest ones that fit. The smallest whole number that is greater than $\frac{5}{3}$ is 2, since $\frac{5}{3}$ is about 1.67.
[*, I can use a calculator to find an approximation of $2\pi$, which is about 6.28. The largest whole number that is less than $2\pi$ is 6, since 7 is too big. So the whole numbers in the interval are 2, 3, 4, 5, and 6. There are 5 of them. 
How many whole numbers lie in the interval between $\frac{5}{3}$ and $2\pi$ ?