The number of ways in which $4$ different things can be distributed to $6$ persons so that no person gets all the things is

If $x={ }^{16} C_5+{ }^{12} C_4, y=\sum_{r=1}^3{ }^{(20-r)} C_4, z=\sum_{k=1}^4{ }^{(16-k)} C_3$,then $x+y+z=$

Let $5$-digit numbers be constructed using the digits $0, 2, 3, 4, 7, 9$ with repetition allowed,and are arranged in ascending order with serial numbers. Then the serial number of the number $42923$ is $...............$.

The total number of numbers lying between $100$ and $1000$ that can be formed with the digits $1, 2, 3, 4, 5$,if the repetition of digits is not allowed and the numbers are divisible by either $3$ or $5$,is:

If the letters of the word $ATTEMPT$ are rearranged randomly,what is the probability that all $T$'s occur together?

The number of times the digit $3$ will be written when listing the integers from $1$ to $1000$ is