global script calculation issues

Hi All.

I created a global script variable Test.

And created two variables m1, m2.

And when trying to calculate sum of M1+M2, i am getting following error:  "Type "Data Cell" Passed but "String/Int/Float" expected for operator "+"

Step 1:

Step 2:

I followed the same steps shown in the following SAP SCN Official Tutorial but still getting the error

Calculate a Value Using Local and Global Script Variables: SAP BusinessObjects Design Studio 1.1 - YouTube

Any kind of suggestions are appreciated

Thanks.