how many divisions in the vernier scale and how many divisions in the main scale ?
Generally a vernier scale has 10 divisions and the main scale has 10 division. But the divisions can be more depending upon the least count of the callipers and type of calliper.
If the scale is constructed in inches then the vernier callipers have 8 divisions
N divisions of Vernier scale are coincident with N-1 divisions of the main scale.