diff --git a/handlers/views_handler_field_math.inc b/handlers/views_handler_field_math.inc
index 08d1e73..bc64f3d 100644
--- a/handlers/views_handler_field_math.inc
+++ b/handlers/views_handler_field_math.inc
@@ -40,6 +40,7 @@ class views_handler_field_math extends views_handler_field_numeric {
     $value = strtr($this->options['expression'], $tokens);
     $expressions = explode(';', $value);
     $math = new ctools_math_expr;
+    $math->fb = array_merge($this->fb, variable_get('views_math_expression_functions', array('time')));
     foreach ($expressions as $expression) {
       if ($expression !== '') {
         $value = $math->evaluate($expression);