The main problem is that jQuery is not loaded when the page is loaded.

if (typeof jQuery != 'undefined') { // jQuery is loaded => print the version alert(jQuery.fn.jquery); }

The first line checks if the jQuery variable has been defined. If it has, it runs the code inside the curly braces. The second line prints an alert with the version of jQuery that’s been loaded.

## Decimal numbers

There are a few ways to work with decimal numbers in jQuery. One way is to use the number() function, which takes an integer input and returns a decimal representation of that number. For example, to get the value of 5.6, you could use the number() function like this:

var num = 5.6;

Another way to work with decimal numbers in jQuery is to use the parseFloat() function. This function takes an input in the form of a string and returns a floating-point representation of that number. For example, if you wanted to get the value of 5.6 as a floating-point number, you could use the parseFloat() function like this:

var num = parseFloat(5.6);

## Math

Math in jQuery is a powerful and easy-to-use library for performing mathematical operations on DOM elements. It includes support for basic arithmetic, trigonometry, and algebra, as well as more advanced features such as matrix operations and vector calculus.

Math in jQuery is built on top of the jQuery Foundation Library, which provides a robust set of cross-browser compatibility features. As a result, Math in jQuery works with both modern browsers (including IE9 and later) and older browsers that don’t support the Foundation Library (such as IE8).

If you’re looking to add some mathematical functionality to your web applications, then Math in jQuery is definitely worth considering.