Find All Combinations That Equal A Given Sum In Excel using formula ( not Solver function )

[Fable09]

Hi everyone,

Can you help me to understand the logic of this formula ?

=IF(ISNUMBER(MATCH(ROWS($1:1),IF(INDEX(MOD(INT((List2-1)/2^(TRANSPOSE(List1)-1)),2),MATCH(TRUE,MMULT(MOD(INT((List2-1)/2^(TRANSPOSE(List1)-1)),2),Range1)=$C$2,0),),TRANSPOSE(List1)),0)),"X",""),

Original tutorial

https://www.extendoffice.com/documents/excel/3557-excel-find-all-combinations-that-equal-given-sum.html

I know if I use Solver function, this tasks can easily be done but I am interested to understand and improve my logical thinking with excel

Thanks,