diff --git a/SqlBuilder.php b/SqlBuilder.php
index 2861d39..dc4885a 100644
--- a/SqlBuilder.php
+++ b/SqlBuilder.php
@@ -189,7 +189,7 @@ class SqlBuilder extends Component
         if (is_null($value)) {
             return $keys;
         }
-        if (is_string($value) && $this->isMath($value)) {
+        if ($this->isMath($value)) {
             $keys[] = $key . '=' . $key . ' ' . $value;
         } else {
             $this->query->pushParam($value);
@@ -205,7 +205,7 @@ class SqlBuilder extends Component
      */
     private function isMath(string $value): bool
     {
-        return str_starts_with($value, '+ ') || str_starts_with($value, '- ');
+		return (bool)preg_match('/^[+|-]\s\d+$/', $value);
     }