How can you return elements between two values?
You’re close! You just need to begin the array with "and":

$criteria = craft()-&gt;elements-&gt;getCriteria(ElementType::User);
$criteria-&gt;customNumberField = array('and', '&gt;=5', '&lt;=10');

$users = $criteria-&gt;find();


This same thing could also be accomplished from your templates like this:

{% set users = craft.users.customNumberField('and', '&gt;=5', '&lt;=10') %}