Isn't that Ohms law I have used.
Yes, that is Ohms law, and it is possible to calculate it using Ohms law, but it is rather convoluted. You calculate the current through the divider, then calculate the voltage drop across one resistor using that current.
It is much easier to calculate the ratio of the resistors (220/(1000+220)) and then multiply that by the voltage across the whole divider. That way you don't need to worry about the current. The ratio will be a static value regardless of the voltage. If you use a voltage divider to, for example, reduce a voltage to fit into the range of an ADC input, then the voltage coming in will be changing. Thus, the current will be changing. Your way would mean calculating the current for every possible voltage to know what the output of the divider would be for that voltage. Using the ratio you know that it will always be a specific proportion of the input.