Answer:
1 tablet
Explanation:
Assuming that gm stands for gram:
Put everything in one unit, 0.3 g = 300 mg.
And given that each tablet is 300 mg:
mass/amount = 300mg / 1 tablet
300mg / X amount = 300mg / 1 tablet
(300mg/300mg) tablet = X = 1 tablet
So it is 1 tablet you need.