This is a question about practical physics .... if its posted in the wrong section my sincere apologies !!!!!!! How do i decide the least count of a measuring device such as an ammeter (analog) ? I know that the least count is the smallest division of measurement ... but why do people take the measurement to the nearest half division ??? Does it have something to do with the pointer(needle) of the ammeter ?? may be its thickness ... i have the same problem with understanding why a measurement made by a metre rule with a least count of 1mm is quoted as say (1.25+/-0.05)cm .