Stxy is correct. One way around the problem is to put the LED's in series if you have enough voltage. The current will be the same in the LED's and only one current limiting resistor is needed. The voltage varies with the current, but the forwrd voltage for red, yellow and green LED's @ 10 Ma the forward voltage is typical of 2V, for orange it is 1.9, for blue it is 3.8 and for white it is 3.2. You can mix colors in series. Just make sure the forward voltage of all the LED's is series is a few tents of a volt less than the applied voltage and then use a current limiting resistor to drop the difference.