12 3 4 x 12 ) 1 4x July 8, 2019 16 32 64 128 12 3 4 x 12 )+ 1 4x 3 4x 1 4 x 12 )- 12 4x 21 12 x 4 / 3 12 x 4 3/4 12 x 4 = 12 x 4 x3
