Hi,

I think your code is very complicated to follow, understand and maintain.

You can use the classes of the buttons to know which class is clicked, to facilitate the writing of your code,

for example in this way :

```
$("button.number").click(function(){
equation += this.name
console.log("eq:" + equation);
})
$("button.sign").click(function(){
equation += this.name
//console.log("equation->sign:" + equation);
})
/*your equal button has an id not a class like other buttons*/
$("button#equal").click(function(){
equation = eval(equation); //this calculate the result of your equation
$("input.grey").val(equation);
//console.log("result of equation:" + equation) ;
});
$(".percent").click(function(){
equation += "/100";
});
$("button.clear").click(function(){
equation="";
$("input.grey").val(0);
});
...etc...
```

Another strange thing, your ''0" button has a class of ‘sign’ !? instead of ‘number’.

You have to reorganize your code for the case of “+/-” button by creating a new class, and just multiply the “equation” by ‘-1’

I hope this will help you.

If you want a link on javascript help you can visit this one w3schools.com.

you have to modify your css to adapt the <input …‘grey’> to fit your

, by giving a

`font-size: 10px;`

for example.

Good luck !