With so many units available to us, converting from unit to unit and moving decimal places can be confusing. There's the Meter, millimeter, micrometer (micron) Feet, Inch and thou and all the imperial fractions as well.

 The  thing to do with the micron is to remember the main unit - the Meter. therefore the micron is 10'-6 or 0.000001= 1 micron. But who works in meter's? far too large a unit, so we use the millimetre which is 10'-3 or 0.001 = 1 millimetre. This is where confusion sets in as we then treat the millimetre as the main unit, the micron is only 10'-3 or 0.001 of a millimetre.

So we could say that 35.99 is actually 36 less 10 microns or 27 less 2 microns is 26.998