Lumber and timbers are measured and sold by board feet. A board foot has a surface 12 x 12 inches and a thickness of one inch. Boards less than an inch in thickness are regarded as an inch thick in selling, but those of any fraction over an inch are sold for what they actually contain.

A specimen bill of lumber is as follows:

(1)

40 p.

2

x

6

x

16

(2)

12 p.

1/2

x

8

x

12

(3)

80 p.

1 1/2

x

6

x

16

(4)

30 p.

l

x

12

x

14

Written in full, the first item, for example, reads 40 pieces 2 inches thick, 6 inches wide, 16 feet long.

The board feet in the 2d and 3d items are as follows:

In item (2), each piece is regarded as having a thickness of one inch. The surface of one piece in square feet is 8/12 X 12; hence the item has a total of 12 x 1 x 8 x 12 / 12 =96 board ft.

In item (3), the surface of each piece is 6/12 x 16 sq. ft., hence the item has a total of 80 x 3/2 x 6/12 x 16 = 960 board ft.