I agree with James C45 here. I know, it sound simple, but to the newbe in electronics, it is not so simple. It a bit comfusing.

OK let analyse this up.

101 ---> you read like a resistor code except the numbers are already there for you. The "unit" is the multiplier. So it is 1 0 0 pF . p is pico 10 exp -12 u is micro 10 exp -6 and n is nano 10 exp -9.

104 ---> is 1 0 --> 0000 <-- 4 zeros so it is 10 0000 pF re-arrange --> 100 000 pF is also 0.1 uF you decimal point is move toward the left 6 position 100 nF , the decimal point is move toward the left 3 position.

In other words... think Metric...