Can the charge of $d$, $s$ and $b$ quarks be thought of as unitary charge? The electron is considered as an elementary particle but nevertheless has three times more charge than any of these three quarks. Is the ratio of electron and one of these quarks the whole number three or are there measurements that show that some decimals are not zero...e.g. 3,0000001245? If all the decimals are zero is this just a coincidence?