Is it acceptable / correct to use integers as class names in this case

Question

I'm creating a simple to use responsive grid and at the moment have following code

.column {
    display: block;
    float:left;
}

.column.12 {
    width: 100%;
}

/* .. */

.column.6 {
    width: 50%;
}

/* .. */

Where integer relates to different size of a column

<div class="column 12"></div>

Above is an example usage.

Answer 1

No. Class names cannot start or be digits. An alternative would be to make class names that end with digits to signify their meaning.

.column12 {
    width: 100%;
}

.column6 {
    width: 50%;
}