divisible by
The divisible by test checks to see if the variable value is evenly divisible by a number.
{% if variable is divisible by(3) %}
...
{% endif %}
Note that there is a space between "divisible" and "by" and "by" has a parameter.
The parameter for the test should be a number.
You can also use a variable for the number parameter.
{% set test = 10 %}
{% set number = 3 %}
{% if test is divisible by(number) %}
<p>{{ test }} is divisible by {{ number }}</p>
{% elseif %}
<p>{{ test }} is NOT divisible by {{ number }}</p>
{% endif %}
In the above example the test would fail because 10 is not evenly divisible by 3. However, if number was 5 then the test would pass because 10 is evenly divisible by 5.