Math can be applied directly to variable values. bar-$bar[1]*$baz->foo->bar()-3*7} {if ($foo+$bar.test%$baz*134232+10+$b+10)} {$foo|truncate:"`$fooTruncCount/$barTruncFactor-1`"} {assign var="foo" value="`$foo+$bar`"} ]]> See also the {math} function for complex equations.