var example_inp = new Array(new Array('1', '1', '2', '+ Add', '2', '2', '3'), new Array('7', '7', '8', '- Subtract', '', '1', '3'),
	new Array('', '1', '2', '* Multiply', '', '1', '3'), new Array('5', '7', '9', '* Multiply', '1', '1', '8'),
	new Array('', '1', '4', '/ Divide', '', '6', '12'));
	
	// decimal, percent
	
	var i = Math.floor(Math.random() * example_inp.length);
	
	function example(){
		var form = document.getElementById('calcForm')
		
		leftWhole = document.getElementById('left_whole')
		leftNumer = document.getElementById('left_numer')
		leftDenom = document.getElementById('left_denom')
		rightWhole = document.getElementById('left_whole')
		rightNumer = document.getElementById('right_numer')
		rightDenom = document.getElementById('right_denom')
		
		leftWhole.value = example_inp[i][0];
		leftNumer.value = example_inp[i][1];
		leftDenom.value = example_inp[i][2];
		rightWhole.value = example_inp[i][4];
		rightNumer.value = example_inp[i][5];
		rightDenom.value = example_inp[i][6];
		
		var cmd = form.operation
		var j;
		for (j = 0; j < cmd.options.length; j++){
			if (cmd.options[j].text == example_inp[i][3]){
				cmd.selectedIndex = j;
				break;
			}
		}
		
		i += 1;
		if (i >= example_inp.length)
			i = 0;
	}