3 7 x 21 8 July 8, 2019 16 32 64 128 3 7 х 8 21 7 8 3 14 x 21 4 3 x 7 )=- 21 8x 3 4 7 8 x 21 2 21 3 7 8 x 2 10 x 21 7 x 3 8 3 5 x 1 21 x 7 8
