Fractions, Decimals, and Percent - Basic Mathematics for Water and Wastewater Operators - page 99

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Whole numberDecimalFractionofanumber

To solve decimal problems, the following key points are important:

1. We often use fractions when dealing with measurements, but it is usually
easier to deal with decimals when we do the calculations, especially when
we are working with pocket calculators and computers.

2. We convert a fraction to a decimal by dividing.

3. The horizontal line or diagonal line of the fraction indicates that we divide
the bottom number into the top number; for example, to convert 4/5 to a
decimal, we divide 4 by 5. Using a pocket calculator, enter the following
keystrokes:

4 ÷ 5 =

The display will show the answer: 0.8.

4. Reading numbers: 23,676 is read as twenty-three thousand six hundred
seventy-six.

5. Relative values of place:
• 0.1 tenths

• 0.01 hundredths

• 0.001 thousandths

• 0.0001 ten thousandths

• 0.00001 hundred thousandths

Note: “And” is not used in reading a whole number but instead is used to signify
the presence of a decimal. For example, 23.676 is read as twenty-three and six
hundred seventy-six thousandths. 73.2658 is read as seventy-three and two thou-
sand six hundred fifty-eight ten thousandths.

■ Example 4.3
Problem : Reduce the following fractions to decimals:
25/27
2/3
19/64
267/425
32/625
1320/2000

Solution:
25/27 = 0.9259
2/3 = 0.6667
19/64 = 0.2969