CREATE TABLE #TEMP(formula NVARCHAR(500))
INSERT INTO #TEMP(formula )
VALUES('((15 * 4) + 1)'),('((15/4) + 1)'),('((15 * 4) *(1+7))');
DECLARE @Grandtot NVarchar(500),@Query NVARCHAR(MAX)
SELECT @Grandtot=STUFF((SELECT '+CAST('+formula+' AS FLOAT)' FROM #TEMP FOR XML
PATH(''),type).value('.','NVARCHAR(500)'),1,1,'');
SET @Query=N'SELECT '+@Grandtot+' AS GrandTot';
EXEC(@Query);
OUTPUT:
GrandTot
545