4. For any real number $x$, $[x]$ represents the greatest integer not exceeding $x$. When $0 \leqslant x \leqslant 100$, the range of the function $f(x)=$ $[2 x]+[3 x]+[4 x]+[5 x]$ contains $\qquad$ different integers.
4. 101 Detailed Explanation: It is easy to see that $f(x+1)-f(x)$ is a constant. Let's first consider the number of different integer values obtained in the interval $0 \leqslant x < 1$. $f(x)$ is a step function on $[0,1)$, and the endpoint values on each segment must be multiples of $\frac{1}{5}, \frac{1}{4}, \frac{1}{3}, \frac{1}{2}$. Within $[0,1)$, there are a total of $0, \frac{1}{5}, \frac{2}{5}, \frac{3}{5}, \frac{4}{5}, \frac{1}{4}, \frac{1}{2}, \frac{3}{4}, \frac{1}{3}, \frac{2}{3}$, which are 10 numbers. Therefore, within $[0,100)$, there are 100 numbers. Since $f(100)$ is also an integer, the range contains a total of 101 different integers.