Leviticus 19:35 "You shall do no unrighteousness in judgment; in length, in weight or in measure"

Your mother likes to be sure she is getting her money's worth when she shops in a fruit and vegetable store.

When she pays for a five pound bag of potatoes, she trusts that she is getting five pounds and that the bag does not weigh any less.

The Torah commands us to make sure that we measure honestly when selling something by the pound, yard or any other measurement.

We may not use an approximate measure.

It is forbidden to cheat a customer and measure his purchase incorrectly.