How to add selected items in a shopping cart using AngularJS?

Hi to all again.

I have the following html table in a task:

I want to write the proper code in order to calculate and display the total sum for the selected items (on checkbox click). Since I select an item I have to fill in the desired quantity.

So, I want to multiply the price by the quantity for each selected item and to add all of the row costs to display the total of my order.

My code is this one:

<form role="form" name="selectForm">
	<script cam-script type="text/form-script">
		camForm.on('form-loaded', function() {																			// The variable 'item' has not been loaded (fetched) from the server yet.
			camForm.variableManager.fetchVariable('item');																// We tell the "Form SDK" to fetch the 'json' variable named 'item'.
		});
		camForm.on('variables-fetched', function() {																	// The variable 'item' has been loaded (fetched) from the server
			$scope.item = camForm.variableManager.variableValue('item');												// and is bound to the current AngularJS $scope of the form.
		});
	</script>
	<h2>My List of Choices</h2>																							
	<div>
		<table style="width:100%;">
			<thead>
				<tr>
					<th style="width:140px;">Category</th>
					<th style="width:305px;">Brief Description</th>
					<th style="width:250px;">Detailed Description</th>
					<th style="width:75px;" >Price</th>
					<th></th>
				</tr>			
			</thead>
			<tbody ng-repeat="x in item track by $index">
				<tr>
					<td><input style="width:140px;" type="text" value="{{x.Category}}" readonly /></td>
					<td><input style="width:305px;" type="text" value="{{x.BriefDescription}}" readonly /></td>
					<td><input style="width:250px;" type="file" value="{{x.DetailedDescription}}" readonly /></td>			
					<td><input style="width:75px;"  type="text" value="{{x.Price}}" readonly /></td>
					<td><input style="width:25px; height:25px;" type="checkbox" ng-model="chkselct"								 					 
							   								    cam-variable-name="isItemSelected"													
							   								    cam-variable-type="Boolean" /></td>
					<td ng-show="chkselct">Quantity: <input style="width:60px;" type="number"
																	   		    cam-variable-name="quantity" min="1"
																	   		    cam-variable-type="Integer" /></td>	
				</tr>
			</tbody>
		</table>
	</div>
</form>

Could anyone help me please?

Thanks in advance,
Steve