gistfile1.js

var Calcs = React.createClass({
    getInitialState: function() {
	return {count: ''};
    },

    handleClickNum: function(index) {
	this.setState({count: index});
    },
    
    render: function() { 
	ParentThis = this;
	var boundCarry = function(Item) {
	    return ParentThis.handleClickNum.bind(ParentThis, Item)
	};	    
    return (
	<div>
	    <Label count={this.state.count}/>
	    <LabeledButtonGrid  boundFun={boundCarry} /> 
        </div>
    )}

});

var LabeledButtonGrid = React.createClass({
    render: function() { 
	boundFun = this.props.boundFun;
	return (
	<div>
	<div className = "row">
		<LabeledButton boundFun={boundFun} number={'1'} addCls={'col-md-3'} />
		<LabeledButton boundFun={boundFun} number={'2'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'3'} addCls={'col-md-3'} />
		<LabeledButton boundFun={boundFun} number={'4'} addCls={'col-md-3'} />
	</div> 
	<div className = "row">
		<LabeledButton boundFun={boundFun} number={'5'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'6'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'7'} addCls={'col-md-3'} />
		<LabeledButton boundFun={boundFun} number={'8'} addCls={'col-md-3'} />
	</div>
	<div className = "row">
		<LabeledButton boundFun={boundFun} number={'9'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'0'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'+'} addCls={'col-md-3'} />
		<LabeledButton boundFun={boundFun} number={'-'} addCls={'col-md-3'} />
	</div>  
	<div className = "row">
		<LabeledButton boundFun={boundFun} number={'X'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'/'} addCls={'col-md-3'} />	
		<LabeledButton boundFun={boundFun} number={'='} addCls={'col-md-3'} />
		<LabeledButton boundFun={boundFun} number={'CE'} addCls={'col-md-3'} />
	</div>
	</div>
	)}
});

var LabeledButton = React.createClass({
    render: function() {
	number        = this.props.number;
	boundClickFun = this.props.boundFun(number);
	classN        = "btn btn-default calcnum " + this.props.addCls;	
	return <button onClick={boundClickFun} className={classN}><h1>{number}</h1></button>;	
    }});

var Label = React.createClass({
    render: function() {
	count = this.props.count;
	return <div> {count} </div>
    }
})

React.render(
  <Calcs />,
  document.getElementById('example')
);

<div className = "row">

а не

<div class="row">

?