How many minimum meiotic divisions have to occur for the formation of 80 male gametes in angiosperms.

In angiosperms, 1 pollen grain has 2 male gametes. 1 microspore mother cell undergoes meiosis to produce 4 microspores which differentiate to form 4 pollen grains. 
Therefore, to form 80 male gamete, there is requirement of 80/2= 40 pollen grains.
To produce 40 pollen grains, there is minimum requirement of 40/4=10 meiosis.