Write the following in exponential form.

$2\times 2\times s\times s\times s\times t\times t$

$a^n$read as a raised to the power of $n$, where $n$ is the exponent or index and $a$ is the base.
The expanded form of $a^n=a\times a\times a\times a......ntimes$.

given expression,

$2\times 2\times s\times s\times s\times t\times t$

Thus,

The exponent of $2\times 2\times s\times s\times s\times t\times t$ $=$ $4s^3{t}^2$