To answer this I would divide 0.666 by 8. Or I could multiply 2/3 by a random near number to get an estimate.
I think I would multiply by 10 so it would be 20/3 which is 6.666 and you can fit another so it is about 7.333 and now I can add another 2/3 so it would be 7.999 therefore the answer would be 12 packets
