Dear Student,
One microspore mother cell gives rise to four pollen grains. And pollen grain undergoes two mitotic division and form 2 male gametes.
Hence ,
1 MMC = 4 pollen grains [Since, 1 pollen grain=2 gamete ]
Hence, 4*2 = 8 male gametes.
16 MMC= 16*4= 64 pollen grains
Hence, Total male gametes= 64*2= 128 gametes.
Regards.