How to use Number Edit Box new value

[#1]

Hello everyone!  I feel like such a novice today.  I cannot seem to find clear information on how to have Number Edit Box values update a Window, other Number Edit Boxes, and equations when values are changed.  My biggest issue is that I have over 30 Number Edit Boxes that feed 2 equations/formulas.  Setting the starting values, I have down.  If a value is changed, everything else needs to update and I can't figure out what I'm missing and online research has led me no further than when I started. 

I have created a small, simple script in hopes of someone here can help me get this understanding through my thick skull.

Thank you all in advance for your knowledge and patience!

doTheMath = function({ val1, val2},
	{result},
	( val1 * val2 ) 
);

var1 = 0;
var2 = 0;

nw = new window( " Testing ",
	<< modal,
	testingVLB = V List Box(
		enterValues = H List Box(
			tbBox1 = Text Box( " Enter Value 1" ),
			nebBox1 = Number Edit Box(var1),
			tbBox2 = Text Box( " Enter Value 2" ),
			nebBox2 = Number Edit Box(var2),
			var1 = nebBox1 << get,
			var2 = nebBox2 << get,
			),
		testResult = doTheMath( var1 , var2),
		tbNothing = Text Box(""),
		if(all(var1!=0, var2!=0), tbResult = Text Box( " Your Result is: " || char( var1 ) || "x" || char( var2 )|| "=" || char( testResult ) ))
	);
);

[#2 · Accepted solution]

Try this code.  You have to use the << set function() construct for number edit boxes.

doTheMath = function({ val1, val2},
	{result},
	( val1 * val2 ) 
);

var1 = 0;
var2 = 0;

// Save the callback steps as an expression because they're the same for both number edit boxes
num_expr = expr(
	var1 = nebBox1 << get;
	var2 = nebBox2 << get;
	if (!isempty(var1) & !isempty(var2),
		testResult = doTheMath( var1 , var2);
		tbResult << set text(char(testresult));
	);
);


nw = new window( "Testing ", << modal,
	testingVLB = V List Box(
		enterValues = H List Box(
			tbBox1 = Text Box( " Enter Value 1" ),
			nebBox1 = Number Edit Box(var1, 10, << set function(num_expr)),
			tbBox2 = Text Box( " Enter Value 2" ),
			nebBox2 = Number Edit Box(var2, 10, << set function(num_expr)
			),
		),
		tbresult = text box(""),
	),
);

[#3]

FANTASTIC!  Thanks so much for getting me back on track.

[#4]

You might want to research the Number Edit Col Box object if you have that many related numeric inputs.

[#5]

Okay, Mark.  I will do that.  Thanks so much.