# Numbers extraction in JavaScript

The `Number` function only works on strings containing numbers. However, when programming in JavaScript, there are often situations where you need to deal with strings that start with a number and then letters.

An example of such a string can be a value in pixels: `'12px'`. Suppose we need to get the number at the beginning, discarding the string part. For such an operation, there is a function `parseInt`. Let's see how it works with an example:

`let num = parseInt('12px'); alert(num); // shows 12`

Pixels, however, are sometimes fractional: `'12.5px'`. In this case, the function `parseInt` passes and prints only the integer part:

`let num = parseInt('12.5px'); alert(num); // still shows 12`

In general, perhaps this behavior is exactly what you need. But if not, use the `parseFloat` function, which extracts the number together with its fractional part:

`let num = parseFloat('12.5px'); alert(num); // shows 12.5`

Of course, the absence of a fractional part does not prevent the `parseFloat` function from working correctly:

`let num = parseFloat('12px'); alert(num); // shows 12`

Given a variable with the value `'5px'` and a variable with the value `'6px'`. Find the sum of pixels from the values of these variables and display it on the screen.

Given a variable with the value `'5.5px'` and a variable with the value `'6.25px'`. Find the sum of pixels from the values of these variables and display it on the screen.

Modify the previous task so that the letters `'px'` are added to the output. That is, if our sum is equal to `11.75`, then let `'11.75px'` be displayed on the screen.

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