You'd like to get rid of the decimals, right? OK, we can do this because it doesn't alter the relative sizes of the numbers, so we can still compare sizes: the greatest number of decimal places is 3 so multiply each number by 1000 (one zero for each decimal place). To multiply by 1000 we move the decimal point three places to the right, putting in zeroes as necessary: the list becomes 210, 201, 1200 and 1020. Now it's easier to see the order 201, 210, 1020 and 1200. Move the decimal point back to where it was: 0.201, 0.21, 1.02 and 1.2.