borrow from the whole number. This proce-
dure is described in detail in Figure 4-7.
Converting Feet to
Inches and Inches to
Feet
It is often necessary to change dimensions
given in inches to equal dimensions in feet and
inches. Since there are 12 inches in a foot, this is
done by dividing dimensions given in inches
by 12, Figure 4-8.
Feet can be changed to inches by multi-
plying the number of feet by 12 (the number of
inches in a foot).
90
Section 1 Introduction to Plumbing
Figure 4-5. Dimensions can be subtracted using the same methods shown in Figure 4-4.
1 2 3 4
1 2 3
4
5 6
53∕4″ – 41∕4″ =
41∕4″
53∕4″
Subtracting the numerators of the fractions
produces the following results:
53∕4″ – 41∕4″ = ______″4∕2
Subtracting the whole numbers gives:
53∕4″ – 41∕4″ = 12∕4″
Now, 2∕4″ can be written in a simpler, reduced form:
53∕4″ – 41∕4″ = 11∕2″
Figure 4-6. Method of subtracting dimensions given in fractions of an inch and having unequal denominators.
1 2 3 4
1 2 3 4 5 6
61∕2″ – 43∕16″ = ______
61∕2″
43∕16″
When the denominators of the fractions are
unequal, the fractions must be changed to equal
fractions having common (equal) denominators.
From Figure 4-1, it can be seen that 1∕2″ = 8∕16″.
Therefore, the above problem can be written as:
68∕16″ – 43∕16″ = ______
Subtracting the fractions produces the following results:
68∕16″ – 43∕16″ = ______″16∕5
Subtracting the whole numbers completes the problem:
68∕16″ – 43∕16″ = 25∕16″
The earliest record of the term plumber
being used is traced to the Roman Empire.
Plumbum is the Latin word for lead, and
Plumbarius means worker in lead. Since lead
was used to make pipe and many fixtures, the
term plumber was an appropriate name for the
trade.
History Brief