15 1 3 x 9 July 8, 2019 16 32 64 128 1 15 x )* 3 8 9 5 1 3 x 15 95 1 5 x 15 )= 1 3 x 9 15 x 1 )=- 3x 9 15 1 2 x 9 3 4 1 3 x 15 )+ 2 3 x 9 1 3 2 9x 15 x 1 3 x 3.14 x 9 x 15 9 x 1 3 15 9 6 15 รท3