How Least Count Is Calculated?

How Least Count Is Calculated? Least count of a Vernier scale is calculated using the following formula, Least count = Smallest reading on main scaleNumber of divisions on Vernier scale=1mm10 = This is the least count for Vernier Callipers. Hence, the least count for Vernier Callipers is 0.1mm. What is the value of least count