Chapter 10 Math 277
When there is one number to the right of the decimal
point that is read as a tenth. Two numbers to the right of
the decimal point are hundredths. Figure 10.4 shows the
decimal, fraction, and written-out expression of various
parts of a whole using multiples of 10.
Example: 28.74 is a decimal fraction. 28 is the whole
number, the (.) is a decimal point, and the numbers to
the right of the decimal point represent the decimal itself.
In the healthcare fi eld, it is standard to always place
a zero to the left of the decimal point when there is not a
digit in that value (for example, 0.95). Putting a zero before
the decimal point prevents misinterpretation, such as reading .95 as the
number 95. Also, a zero after the last digit to the right of the decimal point
is not necessary (1.2, not 1.20).
When writing an equation that features a decimal fraction, you must
remember to properly align all of the numbers. Make sure when you add or
subtract decimal fractions, you line up the decimal points from each number.
Example:
23.45
1.40
+ 451.23
476.08
Converting a Fraction to a Decimal
You will sometimes need to convert fractions to decimals. Converting
a fraction to a decimal is done through a division problem. The fi rst step is
to divide the numerator of the fraction by the denominator. If your fraction
is 2/3, you should divide 3 into 2.
Example: Change the fraction 7/8 to a decimal number.
0.875
8
)7.000
64
60
56
40
40
0
Create a long division problem in which the denominator (8) is divid-
ing into the numerator (7). Add a decimal and zeros to the numerator to
complete the division problem. You can add as many zeroes as you need.
Expressing Parts of a Whole
Decimal Fraction Written-Out
.1 1/10 One-tenth
.01 1/100 One-hundredth
.001 1/1,000 One-thousandth
.0001 1/10,000 One ten-thousandth
Figure 10.4 Expressing parts of a whole
Think It Through
Notice that a gas sta-
tion posts the cost of a
gallon of gas on its sign.
What kind of numbers
do gas stations use to
post the cost of a gallon
of gas?