One tenth of an inch = .1 inches.
If you need to convert them you take the number of inches and move the decimal over one space. Example: 2.0 inches = what number of tenths? 2.0 becomes 20 There are 20 tenths of inches in 2 inches.
It depends on tenths of what!
Divide by 10
4 inches = 4/12 feet = 1/3 foot = 3-1/3 tenths of a foot.