Need help with this javascript code for this calculator!

Hi there! Thank you very much for viewing!

I am working on trying to add these calculators over to this new site that I built with WordPress, but I am having no luck! The HTML and CSS work, but I do not think I am adding the Javascript, as the Calculate and Clear buttons do not function, here at:
http://www.dbhirdotrucking.com/#calculators

I am completely new with JS in WP, but after researching, I added this line code to the themes header.php and calculators-page.php (the template I used for the page):

<script type="text/javascript" src="<?php bloginfo('template_url'); ?>/js/calc.js"></script>

Which references to the calc.js, which is:

<script type="text/javascript">
	function calculate()
	{
		var length =$('.length_ajax').val();
		var width =$('.width_ajax').val();
		var depth =$('.depth_ajax').val();
		var tot = length*width*depth/324;
		var tot = tot.toFixed(2);
		$('.totalcal').val(tot);

		var sf = length*width;
		var sf = sf.toFixed(2);
		$('.squarefeet').val(sf);
	}
	function clearall()
	{
		$('.length_ajax').val('');
		$('.width_ajax').val('');
		$('.depth_ajax').val('');
		$('.totalcal').val('');
		$('.squarefeet').val('');
	}
	</script>

I have spent days trying to figure this out on my own, but I really need help please! Any attempts to help are GREATLY appreciated!

Thanks for reading!!!
Mike