If you want this calculator simply copy and paste the below html. You can edit the colours by changing the codes in red. (go to colour chart to choose colours)
The Code:
<html>
<head>
<title>Cool Blue Calculator</title>
</head>
<body>
<form name="calculator">
<!-- keep the display colours the same as the table colours -->
<table border="4" cellpadding="1" bordercolor="#0066CC" bgcolor="#000033" cellspacing="2" width="222">
<tr>
<td>
<input type="text" size="25" length="25" value="" name="ans" style="background:beige;color:black;">
</td>
</tr>
</table>
<!-- the keypad was made with a table and forms placed in the spaces -->
<table border="4" cellpadding="2" bordercolor="#0066CC" cellspacing="2" width="150" bgcolor="#000033">
<tr>
<td align="center">
<input type="button" value=" 7 " name="seven" onClick="document.calculator.ans.value+='7'">
</td>
<td align="center">
<input type="button" value=" 8 " name="eight" onClick="document.calculator.ans.value+='8'">
</td>
<td align="center">
<input type="button" value=" 9 " name="nine" onClick="document.calculator.ans.value+='9'">
</td>
<td align="center">
<input type="button" value=" / " name="divide" onClick="document.calculator.ans.value+='/'">
</td>
</tr>
<tr>
<td align="center">
<input type="button" value=" 4 " name="four" onClick="document.calculator.ans.value+='4'">
</td>
<td align="center">
<input type="button" value=" 5 " name="five" onClick="document.calculator.ans.value+='5'">
</td>
<td align="center">
<input type="button" value=" 6 " name="six" onClick="document.calculator.ans.value+='6'">
</td>
<td align="center">
<input type="button" value=" * " name="multiply" onClick="document.calculator.ans.value+='*'">
</td>
</tr>
<tr>
<td align="center">
<input type="button" value=" 1 " name="one" onClick="document.calculator.ans.value+='1'">
</td>
<td align="center">
<input type="button" value=" 2 " name="two" onClick="document.calculator.ans.value+='2'">
</td>
<td align="center">
<input type="button" value=" 3 " name="three" onClick="document.calculator.ans.value+='3'">
</td>
<td align="center">
<input type="button" value=" - " name="subtract" onClick="document.calculator.ans.value+='-'">
</td>
</tr>
<tr>
<td align="center">
<input type="button" value=" C " name="clear" onClick="document.calculator.ans.value=''">
</td>
<td align="center">
<input type="button" value=" 0 " name="zero" onClick="document.calculator.ans.value+='0'">
</td>
<td align="center">
<input type="button" value=" = " name="equal"
onClick="document.calculator.ans.value=eval(document.calculator.ans.value)">
</td>
<td align="center">
<input type="button" value=" + " name="add" onClick="document.calculator.ans.value+='+'">
</td>
</tr>
</table>
</form>
</body>
</html>