PART E - DECIMALS
Reading decimals. The figure to the right of the decimal point indicates the number of tenths. For example -
.6 is the same as 6/10. The further to the right of the decimal, the smaller the fraction. Two figures to the
right indicate hundredths; three means thousandths and so on.
Adding and subtracting decimals: when adding or subtracting decimals you must use the same method
of adding whole numbers. All the numbers must be lined up in vertical columns, but the decimal points must
be in a straight line.
Multiplying decimals: decimal fractions are multiplied the same way whole numbers are multiplied;
however, once the product is found, you move the decimal point as many places from the right as there were
in both the multiplicand and the multiplier.
The number 18.6 has one decimal place and 5.27 has two. The total is three decimal places. The
product 98022 must show those three decimal places. The correct answer is 98.022.
Dividing decimals: decimal fractions are divided the same way as whole numbers except one step must
be done before any division is done. The first step is to move the decimal in the divisor over the number of
spaces necessary to make it a whole number. Then move the decimal in the dividend the same number of
spaces. Place the decimal point directly over the dividend and then divide.
For Example: 0.875 ,, 0.5 = 1.75
Converting decimals to percents and percents to decimals: To convert a decimal to a percent just move
the decimal over to the right two places and put the % sign after the number. To convert a percent to a
decimal move the decimal point two places to the left and remove the % sign.
PART F - PERCENTAGES
To find the percentage of any number, change the percent to a decimal fraction and multiply by the number.
Example: 15% of 100. (The decimal fraction of 15% is .15) .15 x 100 = 15
Rate ,, Base = Percentage. Base is a quantity of which a certain percent is desired. It is the starting
point, the part that you want to break down. Rate is the amount or percent of the base you want.
Example: A fuel tank contains 130 bbls of fuel. 2.6 bbls is BS&W. What percent of the tank is BS&W?
130 = Base 2.6 = rate
2.6 = 2%
PART G - AREA
Area is the measurement of a surface expressed in square units. The top of your desk or the surface of the
chalkboard are examples of area. We cannot state the length in meters and width in yards. There is no such
measurement as meter yards. We must measure or convert all measurements to one unit of measurement.
To convert units of measurements do the following:
Square inches to square feet ,, by 144
Square inches to square yards ,, by 1,296
Square feet to square inches x by 144
Square feet to square yards ,, by 9
Square yards to square feet x by 9
Square yards to square inches x by 1,296
Before using the formulas below you must make sure that all measurements are in the same unit.
A=LXW L=A,,W W =A,,L