Practical Units

The three forms of ohms law can be used to practical units current,potential difference,and resistance as follows:
1 ampere = 1 volt/1 ohm

1volt = 1ampere x1 ohms

1 ohm = 1volt /1ampere
One ampere is the amount of current through a one-ohm resistance that has one volt of potential difference applied acrossit.
One volt is the potential difference across a one-ohm resistance that has one ampere of current through it.
One ohm is the amount of opposition in a resistance that has a V/I ratio of 1, allowing one ampere of current with one volt applied.

A triangle diagram to help in memorizing the ohms law formula V=IR, and R=V/I. The V is always at the top.