How to give a LED, a certain mA value in a circuit ?

Question

The assignment is this:

Make a circuit with 9 LED's where the currents are different depending on the student's ID (this is my id 161738062, so LED 1 is 1mA, LED 2 is 6mA, LED 3 is 1mA, LED 4 is 7mA, LED 5 is 3mA, LED 6 is 8 mA, LED 7 is 10mA, LED 8 is 6mA and LED 9 is 2mA - for number 0 use 10mA). LED's work with 0.7V and the circuit is powered by a 12V power source, while the maximal power of the source is 10W. 

The aim is that the LED's to use that certaim mA power. Calculate the power needed to supply all the LED's.

I'm stuck at the part of giving each LED their certain mA, should I use a certain value resistor or what ?

Answer

Each LED is a series circuit with one resistor. The LED drops 0.7 volt, the resistor drops 11.3 volts, so the resistance is found by Ohm's law. R = 11.7V/I

Total current = 1 + 6 + 1 + 7 + 3 + 8 + 10 + 6 + 2 = 44 mA
Power = 12V x 44mA = 528 mW

How to give a LED, a certain mA value in a circuit ?

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