Is it possible to convert to binary from decimal on the fly?

Question

Programming

All my life I have been able to convert to binary from the decimal system as follows: I took a number, constantly divided by 2, then took the remainder, which was always 0 or 1 (the standard scheme, in general, which is taught).
But I want to learn how to translate without a leaflet, on the fly. I heard about some BCD (8421) weights and did not understand anything. Is someone familiar with such a methodology, and can explain "on the fingers" how to do it? Or maybe someone has a simpler tactic for transferring from 10 to 2 SS?

Answer 1

Or maybe someone has a simpler tactic for transferring from 10 to 2 SS?

Most IT people know powers of two by heart, like a multiplication table. For example "1001" is 512+256+128+64+32+8+1 or 1024-16-4-2-1 which is 1111101001 This is pretty easy to count in your head without paper.