Question: how many a4 sheets in 1 kg?
Answer: By definition there are 16 sheets of A4 paper in 1 m² ( = A0 ), so one sheet of A4 paper has a weight of 80/16 = 5 g. So the answer is that 200 sheets of A4 paper have a weight of 1 kg. What size of paper is required to make a bag of A4 size?