Dim Score As double 'or as Long, but not as Integer. Integer limit is 32K
Dim Result as double
score = Range("G2")
If score > 50001 Then result = Sheets("ABC").Range("D2")*1.022 'More concise than addition and multiplication
Range("K2") = result
'Or Range("K2") = CStr(result). But you can't perform math on a Textual number.
'Even If 1 < "2" will fail
If you want a formula in K2 then use
Dim Result as String
Range("K2").Formula = result
Where Result = "=SUM(ABC!D2)+(ABC!D2*2.2%)"
Or, where Result = "=ABC!D2*1.022"