# Array keys in variables in JavaScript

Let's say we have an array like this:

`let arr = ['a', 'b', 'c'];`

Let's display the element with the key `0`:

`let arr = ['a', 'b', 'c']; console.log(arr[0]); // shows 'a'`

Let's now not write the key of the displayed element directly in square brackets, but write it into a variable:

`let arr = ['a', 'b', 'c']; let key = 0; // write the key to a variable`

We now use our variable to display the corresponding element:

`let arr = ['a', 'b', 'c']; let key = 0; // write the key to a variable console.log(arr[key]); // shows 'a'`

Given the following array:

`let arr = ['a', 'b', 'c'];`

Also given the variable:

`let key = 2;`

Display the element whose key is stored in the variable `key`.

Given the following array:

`let arr = [1, 2, 3, 4, 5];`

Also given the variables:

`let key1 = 1; let key2 = 2;`

Find the sum of elements whose keys are stored in our variables.

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