1 2 20 x 2 3 4 July 8, 2019 16 32 64 128 1 2 20 x 3 4 bolt 1 2 20 x 1 3 4 grade 5 carriage bolt 1 2 6x 20 )= x 4 2 x 3 3 2 4 2x )+ 1 20 2 2 x 1 - 2 = 4 1 2 + 3 4 1 + 2 + 3 + 4 = 10