Let now we store not a number in quotes in
a variable, but just a number. In this case,
an attempt to access its individual character
will return `undefined`

,
since such an access only works for strings:

```
let test = 12345;
alert(test[0]); // shows undefined
```

let's convert our number to a string to solve the problem:

```
let test = String(12345); // string
alert(test[0]); // shows '1' - everything works
```

Suppose now we want to find the sum of the first two digits:

```
let test = String(12345); // string
alert(test[0] + test[1]); // shows '12' - concatenates like strings
```

Let's add the function `Number`

so
that the characters are summed as numbers:

```
let test = String(12345); // string
alert(Number(test[0]) + Number(test[1])); // shows 3
```

I remind you that a problem of this kind will arise only with summation. When multiplying, for example, conversion to numbers can be omitted:

```
let test = String(12345); // string
alert(test[1] * test[2]); // shows 6
```

The number given is `12345`

.
Find the sum of the digits of this number.

The number given is `12345`

.
Find the product of the digits of this number.

The number given is `12345`

.
Rearrange the digits of this number in reverse order.