8/7/2008

On 8/7/08 was my first class in math108. It was really excited because since primary school mathematic is my favorite subject. Today my lecturer will lecture about FRACTION, DECIMAL, PERCENTS, and RATIO. Here some notes
that I can share with all of you:



FRACTION

-A number that can be written as a quotient of two quantities is called a fraction.

1 and 3
E.g., - -
2 4


-The number above the line in a fraction is called the numerator and it tells how many parts are being talked about or considered. The number below the line in a fraction is called the denominator and it indicates the number of parts in the whole. It tells what kind or size of parts the numerator counts.


DECIMAL

-Decimals are another to express fraction and decimals that are based on hundredths. For examples, 1 3
E.g., - = 0.5 and - = 0.75
2 4


PERCENTAGES

-Percentages are simply another way of representing fraction and decimal that are based on hundreds. For examples, 0.12 can be through as12%. “Percent” means “per
hundred” or “for ever hundreds.” S, 12% is a way of representing 12 for every 100. Percents are an easy to compare data because they have to common base of 100.









Conversation Between Fraction, Decimal and Percentage


-Conversation a Fraction to a Percent

Convert 4/5 to a percent

STEP 1: Divided the numerator of the fraction by the denominator 4/5=0.80

STEP 2: Multiply by 100% (move to the decimal point two places 0.80x100%
to the right) =80%

-Conversation a Percent to a Fraction

Convert 80% to a fraction

STEP 1: Remove the percent sign 80

STEP 2: Make a fraction with the percent as the numerator and 80/100
100 as the denominator

STEP 3: Reduce the fraction if possible 4/5


-Converting a Decimal to a Percent

Convert 0.83 to a percent

STEP 1: Multiply the decimal by 100 0.83x100%

STEP 2: Leave the answer in a percent sign 83%


-Converting a Percent to a Decimal

Convert 83% to a decimal

STEP 1: Divide the percent by 100 80/100






Ratio and Proportions

-Ratio

A ratio is a comparison of two or more quantities. Ratio can be written using fraction or colon (:). For examples, if comparing 60kg 40 40kg, the comparison may be express in the same unit of measurement. Do not write the unit of measurement in ratio.

It is important to note that ratios represent relative, rather than absolute, amount. For examples, if the ratio of boy to girl in particular grade level is 2 to 3, there could be 20 boys and 10 girls, 200 boys and 200 girls, or some other pair of numbers whose is equivalent (e.g. 40 boys and 60 girl).


-Proportions

Proportions are equivalent ratios. Each proportions consist of four terms. For example,1 is to 3 as 2 is to 6 is a proportion. It can be written as the follow:

1:3 = 2:6 or 1/3 = 2/6

Proportion may be direct or inverse. In direct proportion, as one ratio increase (or decrease) so does the other. In inverse proportion, as one ratio increase the other decrease and vice versa.
As a guide for setting up equation in dealing with
Direct proportion:
1. Write the ratio using like unit
2. Write the second ratio in the same order, so that its numerators is term that pertains to the numerator of the first ratio.

1. Write the ratio using the like units.
2. Write the second ratio in the inverse order, so that its numerators is the term that pertains to the denominator of the first ratio.