Fiz uma calculadora utilizando javascript
<title>Micro Calculadora</title> <style type="text/css"> input[type=number]{ width: 100%; padding: 12px 20px; margin: 8px 0; box-sizing: border-box; border: 2px solid #ccc; border-radius: 4px; background-color: #f8f8f8; font-size: 20px; } input[type=button]{
background-color: #4CAF50;
border: none;
color: white;
padding: 16px 32px;
text-decoration: none;
margin: 4px 2px;
cursor: pointer;
font-size: 20px;
}
</style>
<input type="button" value="+" onclick="add()">
<input type="button" value="-" onclick="sub()">
<input type="button" value="*" onclick="mul()">
<input type="button" value="/" onclick="div()">
<p id="result"></p>
<script type="text/javascript">
function add(){
var num1 = parseInt(document.getElementById('num1').value);
var num2 = parseInt(document.getElementById('num2').value);
var result = num1 + num2;
document.getElementById('result').innerHTML = "Resultado: " + result;
}
function sub(){
var num1 = parseInt(document.getElementById('num1').value);
var num2 = parseInt(document.getElementById('num2').value);
var result = num1 - num2;
document.getElementById('result').innerHTML = "Resultado: " + result;
}
function mul(){
var num1 = parseInt(document.getElementById('num1').value);
var num2 = parseInt(document.getElementById('num2').value);
var result = num1 * num2;
document.getElementById('result').innerHTML = "Resultado: " + result;
}
function div(){
var num1 = parseInt(document.getElementById('num1').value);
var num2 = parseInt(document.getElementById('num2').value);
var result = num1 / num2;
document.getElementById('result').innerHTML = "Resultado: " + result;
}
</script>