
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body {
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
background: rgb(80, 80, 90);
}
.calculator {
display: grid;
position: relative;
}
.calculator .value {
grid-column: span 4;
text-align: right;
outline: none;
padding: 10px;
border-radius: 8px;
border: 1px solid #6b6364;
width: 240px;
height: 80px;
color: aliceblue;
font-weight: 700;
font-size: 30px;
background: #565759;
}
.calculator .num {
display: flex;
justify-content: center;
align-items: center;
border: 1px solid #565759;
background: rgba(124, 124, 124, 0.842);
width: 60px;
height: 60px;
color: aliceblue;
}
.calculator span.zero {
grid-column: span 2;
width: 120px;
}
.calculator span.ac {
grid-column: span 3;
width: 180px;
}
</style>
<body>
<form class="calculator" name="calc">
<input type="text" class="value" name="txt">
<span class="num ac" onclick="document.calc.txt.value = ''">AC</span>
<span class="num" onclick="document.calc.txt.value += '/'">/</span>
<span class="num" onclick="document.calc.txt.value += '7'">7</span>
<span class="num" onclick="document.calc.txt.value += '8'">8</span>
<span class="num" onclick="document.calc.txt.value += '9'">9</span>
<span class="num" onclick="document.calc.txt.value += '*'">*</span>
<span class="num" onclick="document.calc.txt.value += '4'">4</span>
<span class="num" onclick="document.calc.txt.value += '5'">5</span>
<span class="num" onclick="document.calc.txt.value += '6'">6</span>
<span class="num" onclick="document.calc.txt.value += '-'">-</span>
<span class="num" onclick="document.calc.txt.value += '1'">1</span>
<span class="num" onclick="document.calc.txt.value += '2'">2</span>
<span class="num" onclick="document.calc.txt.value += '3'">3</span>
<span class="num" onclick="document.calc.txt.value += '+'">+</span>
<span class="num zero" onclick="document.calc.txt.value += '0'">0</span>
<span class="num" onclick="document.calc.txt.value += '.'">.</span>
<span class="num" onclick="document.calc.txt.value = eval(calc.txt.value)">=</span>
</form>
</body>
</html>