Calculation using alphabet instead if number

Hello,

Dear Sir,
If I assumed A=1 B=2 C=3 D=4 F=5 G=6 H=7 I=8 J=9 K=0
For example
Numeric column > 9949 = JJDK <English Letter column
Numeric column > 9949 = JJDK <English Letter column
TOTAL Numeric column >19898 =AJIJI <TOTAL English Letter column
HOW CAN I CALCULATE THIS USING FORMULA IN MS EXCEL
Waiting for your great replay sir thanks a lot sir. Thank you very much sir