How to read the metric version of vernier calipers?

Regarding to the metric version of vernier caliper, there are three kinds of graduations: 0.1mm, 0.02mm, 0.05mm. How to read the metric version of vernier calipers correctly?

For the metric version of vernier caliper, each graduation on the main scale is 1.00mm. Every tenth graduation is numbered in sequence - 10 mm, 20 mm, 30 mm, 40 mm, etc. …over the full range of the scale. It provides for direct reading in millimeters. The Vernier scale is graduated in 50 parts, each represents 0.02 mm. Every fifth line is numbered in sequence - 0.10 mm, 0.20 mm, 0.30 mm, 0.40 mm, 0.50 mm - providing for direct reading in hundredths of a millimeter.

Here we take the graduation of 0.02mm for example:

Three steps for reading the metric version of vernier caliper:

1. To count how many mm's line between the 0 line on the main scale and the 0 line on the Vernier scale. It is 23mm on the main scale.
2. Then to find the line on the vernier scale which exactly coincides with the line on the main scale. The twentieth line coincides with the line on the main scale, so 20x0.02mm=0.4mm
3. Finally, add the reading in hundredths on the vernier scale to the reading on the main scale. 23mm+0.4mm=23.4mm