Want to make short a formula

Hi,

I have created a formula to find out last digit of 18 digit numbers. Actually I got this formula by using lugn algorithm. Here is the formula. Also attached a sample file in this regards.

Formula:

=IFERROR(A2&IF(VALUE(RIGHT(MID(A2,1,1)+IF(LEN(MID(A2,2,1)*2)=2,RIGHT(MID(A2,2,1)*2,1)+LEFT(MID(A2,2,1)*2,1),MID(A2,2,1)*2)+MID(A2,3,1)+IF(LEN(MID(A2,4,1)*2)=2,RIGHT(MID(A2,4,1)*2,1)+LEFT(MID(A2,4,1)*2,1),MID(A2,4,1)*2)+MID(A2,5,1)+IF(LEN(MID(A2,6,1)*2)=2,RIGHT(MID(A2,6,1)*2,1)+LEFT(MID(A2,6,1)*2,1),MID(A2,6,1)*2)+MID(A2,7,1)+IF(LEN(MID(A2,8,1)*2)=2,RIGHT(MID(A2,8,1)*2,1)+LEFT(MID(A2,8,1)*2,1),MID(A2,8,1)*2)+MID(A2,9,1)+IF(LEN(MID(A2,10,1)*2)=2,RIGHT(MID(A2,10,1)*2,1)+LEFT(MID(A2,10,1)*2,1),MID(A2,10,1)*2)+MID(A2,11,1)+IF(LEN(MID(A2,12,1)*2)=2,RIGHT(MID(A2,12,1)*2,1)+LEFT(MID(A2,12,1)*2,1),MID(A2,12,1)*2)+MID(A2,13,1)+IF(LEN(MID(A2,14,1)*2)=2,RIGHT(MID(A2,14,1)*2,1)+LEFT(MID(A2,14,1)*2,1),MID(A2,14,1)*2)+MID(A2,15,1)+IF(LEN(MID(A2,16,1)*2)=2,RIGHT(MID(A2,16,1)*2,1)+LEFT(MID(A2,16,1)*2,1),MID(A2,16,1)*2)+MID(A2,17,1)+IF(LEN(MID(A2,18,1)*2)=2,RIGHT(MID(A2,18,1)*2,1)+LEFT(MID(A2,18,1)*2,1),MID(A2,18,1)*2),1))=0,0,10-VALUE(RIGHT(MID(A2,1,1)+IF(LEN(MID(A2,2,1)*2)=2,RIGHT(MID(A2,2,1)*2,1)+LEFT(MID(A2,2,1)*2,1),MID(A2,2,1)*2)+MID(A2,3,1)+IF(LEN(MID(A2,4,1)*2)=2,RIGHT(MID(A2,4,1)*2,1)+LEFT(MID(A2,4,1)*2,1),MID(A2,4,1)*2)+MID(A2,5,1)+IF(LEN(MID(A2,6,1)*2)=2,RIGHT(MID(A2,6,1)*2,1)+LEFT(MID(A2,6,1)*2,1),MID(A2,6,1)*2)+MID(A2,7,1)+IF(LEN(MID(A2,8,1)*2)=2,RIGHT(MID(A2,8,1)*2,1)+LEFT(MID(A2,8,1)*2,1),MID(A2,8,1)*2)+MID(A2,9,1)+IF(LEN(MID(A2,10,1)*2)=2,RIGHT(MID(A2,10,1)*2,1)+LEFT(MID(A2,10,1)*2,1),MID(A2,10,1)*2)+MID(A2,11,1)+IF(LEN(MID(A2,12,1)*2)=2,RIGHT(MID(A2,12,1)*2,1)+LEFT(MID(A2,12,1)*2,1),MID(A2,12,1)*2)+MID(A2,13,1)+IF(LEN(MID(A2,14,1)*2)=2,RIGHT(MID(A2,14,1)*2,1)+LEFT(MID(A2,14,1)*2,1),MID(A2,14,1)*2)+MID(A2,15,1)+IF(LEN(MID(A2,16,1)*2)=2,RIGHT(MID(A2,16,1)*2,1)+LEFT(MID(A2,16,1)*2,1),MID(A2,16,1)*2)+MID(A2,17,1)+IF(LEN(MID(A2,18,1)*2)=2,RIGHT(MID(A2,18,1)*2,1)+LEFT(MID(A2,18,1)*2,1),MID(A2,18,1)*2),1))),"")

This formula is working fine. I need this formula in short. Please help me by doing this.