To read the mike you need to understand the Thimble and the Sleeve.
The Sleeve does not move. It looks like a ruler with ten numbers. The space between each number is divided into quarters. As the Thimble rotates around this Sleeve it covers up, or reveals the numbers marked on the Sleeve.
It is easy to read a micrometer if you think of the markings on the Sleeve as dollars and quarters.
If you think of the lines on the Sleeve as dollars and quarters, then the lines on the Thimble represent "pennies," or cents. As the thimble rotates, you add those pennies to the dollars and quarters.