The div tag accepts two parameters and returns as its output the value obtained after dividing the first parameter by the second parameter.
The parameters may be literal strings, variables or output of other tags.
<cms:div my_count '5' />
The snippet divides by 5 whatever value is contained within my_count variable and outputs the resulting value.
The tag expects two parameters as the operands for division.
This tag is self-closing and does not set any variables of its own.