Question

If there are 8 division between the 0 mark and 0.4 A mark of an ammeter ,its least count is

Answer 1

As you cans see the number. of divisions is 8
the mark is of 0.4
from the formula you cab evaluate 
the least count = total no.of mark divided by no. of divisions
=0+0.4/8=0.05

Answer 2

$\bold{\text{Least count }}=\frac{\bold{Range}}{\bold{\text{number of divisions}}}$
Here given Range is ( 0.4A - 0A) = 0.4A
number of divisions in ammeter scale = 8
Least count = 0.4/8 = 0.05

Hence, Least count of ammeter is 0.05