diff --git a/text_to_sql_query.rb b/text_to_sql_query.rb
index f0bbce2..720a46b 100644
--- a/text_to_sql_query.rb
+++ b/text_to_sql_query.rb
@@ -41,8 +41,8 @@ class TextToSqlQuery
         raise "There should be more than 1 element for expression following NOT operator"
       end
 
-      not_expression = not_array.first
-      not_params = not_array[1..]
+      not_expression = not_array.shift
+      not_params = not_array
 
       ["NOT #{not_expression}"] + not_params
 
@@ -74,11 +74,11 @@ class TextToSqlQuery
       raise 'There should be more than 1 element in second operand array'
     end
 
-    first_operand_expression = first_operand.first
-    first_operand_params = first_operand[1..]
+    first_operand_expression = first_operand.shift
+    first_operand_params = first_operand
 
-    second_operand_expression = second_operand.first
-    second_operand_params = second_operand[1..]
+    second_operand_expression = second_operand.shift
+    second_operand_params = second_operand
 
     ["(#{first_operand_expression} #{operator.to_s} #{second_operand_expression})"] + first_operand_params + second_operand_params
   end