I used `round()` function to show the file size in from byte to MB.

The data was like the following-

```
file_size
----------
2463

```

I used this to convert-

```
round(document.file_size / (1024*1024), 3) file_size

```

Now the data is showing like this-

```
file_size
----------
.002

```

But, what I want is like this-

```
file_size
----------
0.002

```

Just the left most zero. How can I have this?