How will u calculate 100ppm of gibberllice acid

I don't understand your question...

It is as if you were asking how to calculate 1 metre or 1 foot...

Do you need to prepare a solution of 100 ppm gibberllic acid? If so, 100 ppm means 1 kg in 1000000 litres, or 1 mg in 1 litre.

So 100 ppm means you need 100 mg of gibberllic acid in 1 litre of solution.