Thats not actually true for "this page", but I know what you mean.
19,000 / 630 = about 30 sheets of A4 paper to cover an average adults body.
You may be on to a new fashion trend here.
You dont need the 0.5mm or the 4mm at all. The question is simply asking: How many sheets of 630-sq-cm each do you need in order to cover 19,000 sq cm?
An AHA peeling solution has pH of 3.83 what would be the percentage available acid 3%(pH3) glycolic and the percentage of salt? Could you me its really urgent