1 gram is roughly equal to 1 small paper clip or pen cap. Now how many flies would you have to put on the scale to equal the mass of a paperclip? 10? 100? 100? Actually a house fly has a mass of about 9-10 mg or 0.01 grams. If you thought about 10 flies would equal a paperclip then you would come up with 0.1 gram. While 0.01 is the best answer if you estimated 0.1 gram a little high but not a bad estimate.