You'll note that English is written left to right. In the string "20%" there is a "2", a "0", and a "%" arranged from left to right. To type that string into a

You'll note that English is written left to right. In the string "20%" there is a "2", a "0", and a "%" arranged from left to right. To type that string into a calculator, one could press "2", "0", and "%" in that order, or "0", ".", "2", in that order. To know to lead with "0." rather than "20", you have to look ahead. For the others you'd have to do the mental work to append a 1 regardless, might as well stick with decimals