I can make one cigar from 7 butts, and I have 187 butts, how many full cigars can I make and smoke in total?

Ask your math teacher how you are going to find leaf tobacco to wrap those vile cigars. Or hurry on over to homework help in Education and Reference an ask your question there.

Put those butts back in the gutter, you fool.

That sounds so horrible. Not ignoring the fact a good cigar is wrapped in a certain way with certain kinds of whole or purposefully cut leaves by skilled craftsmen, but the tar that came through your butts is going to taste and smell like when you scrapped the tar out of your weed pipe when you were out of weed in the 8th grade. 

Do you also go on your knees to snort up whatever crack landed on the shag carpeting, like Hunter Biden? 

187 will yield 26 full second generation cigars with 5 left over butts.

So 26 cigars.

After burning those, you have 26 second generation butts plus the 5 initial ones.

Those 31 allow the fabrication of 4 third generation cigars, with 3 butts left over.

So far, 30 cigars.

Now you have 4 third generation butts and 3 second generation ones, enough for one last cigar.

So, total 31.