In the array shown below, three $3$s are surrounded by $2$s, which are in turn surrounded by a border of $1$s. What is the sum of the numbers in the array?

$$\begin{array}{ccccccc} 1 & 1 & 1 & 1 & 1 & 1 & 1 \\ 1 & 2 & 2 & 2 & 2 & 2 & 1 \\ 1 & 2 & 3 & 3 & 3 & 2 & 1 \\ 1 & 2 & 2 & 2 & 2 & 2 & 1 \\ 1 & 1 & 1 & 1 & 1 & 1 & 1 \\ \end{array}$$

Video solution:

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Written solution:

There are $20$ border entries equal to $1$, $12$ entries equal to $2$, and $3$ entries equal to $3$. The sum is $20\cdot1+12\cdot2+3\cdot3=20+24+9=53$.