The word "didst number on" is a combination of the archaic past tense of "do" which is "didst," and the phrasal verb "number on." When pronounced, "didst" sounds like /dɪdst/ and the stress is on the first syllable. "Number on" is pronounced as /ˈnʌmbər ɒn/ with the stress on the first syllable of "number." This phrase means to count or include something in a list. It's important to note that this phrase is considered archaic and is no longer widely used.