How To Fix GB307 - Field &1 not permitted in mathematical expressions

SAP Error Message - Details

• Message type: E = Error

• Message class: GB - Messages used by the Boolean code generator

• Message number: 307

• Message text: Field &1 not permitted in mathematical expressions

What causes this issue?

You used the field &V1& within a mathematical expression. The field
is not valid in the expression.
Only fields that can also make calculations are allowed to be used in
the expression. Valid data types are amounts, quantities an numbers.
Invalid data types are character strings like types, that are partially
made up of character strings.
Example:
MATHS( SUM( <BSEG> $DMBTR ) > 0 ) allowed
MATHS( SUM( <BSEG> $&V1& ) > 0 ) not allowed since field
&v1& is not numerical

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

The mathematical expression is recognized as containing an error and
is not accepted.

How to fix this error?

Use fields in your mathematical expression with which you can perform
mathematical operations.
You can find additional information about using mathematical expression
und the topic <DS:DE.BOOLEXP>Boolean syntax</>

Error message extract from SAP system. Copyright SAP SE.