# In how many ways can 5 identical rings can be worn on 4 fingers?

$\begin{array}{1 1} ^5C_4 \\ 4^5 \\ 5^4 \\ 5! \end{array}$

Since no condition is given,
Any of the rings can be worn on any finger.
i.e., Each ring has 4 options.
There are 5 rings.
The required no. of ways = $4^5=1024$