Pergunta de entrevista da empresa Microsoft

Interviewer first question: "Why Microsoft" and then he shares a Codility link. Question: Convert a number (1234) into words (One Two Three Four) in a most efficient way(no switch case), no string conversion etc. Since I didn't practice much Algorithms, I struggled a bit, however the interviewer gave some tips. It was a 50 mins online test in 1 hr time slot.