I am trying to make a calculator in javascript and it is not working. When I try to do, say 1 + 1 it gives me 11 and this is the same for all the numbers here is my code:

```js
var slider1 = document.getElementById("myRange1");
var slider2 = document.getElementById("myRange2");
var output = document.getElementById("output");
var fullEquat = document.getElementById("equation");
var add1 = slider1.value;
var add2 = slider2.value;

output.innerHTML = slider1.value; // Display the default slider value

// Update the current slider value (each time you drag the slider handle)
slider1.oninput = function() {
  output.innerHTML = this.value;
}
slider2.oninput = function() {
    add1 = slider1.value;
    add2 = slider2.value;
    equals = add1 + add2;
  fullEquat.innerHTML = slider1.value + "+" + slider2.value + "=" + equals;
}
slider1.oninput = function() {
    add1 = slider1.value;
    add2 = slider2.value;
    equals = add1 + add2;
  fullEquat.innerHTML = slider1.value + "+" + slider2.value + "=" + equals;
}
```

```css
.slider {
    width: 400px;
    display: inline;
}
.equal {
    text-align: center;
    font-size: 100pt;
    margin: 0 0 0 0;
}
```

```html
<div class="slidecontainer">
  <input type="range" min="0" max="1000" value="500" class="slider" id="myRange1">
    +
  <input type="range" min="0" max="1000" value="500" class="slider" id="myRange2">
</div>
<p class="equal">=</p>
<p id="output" class="output"></p>
<p id="equation" class="equat"> + = </p>
```