Welcome to percentage preparation! A percentage is simply a way to express a fraction out of one hundred. The word percent means per hundred. For example, if twenty five out of one hundred students pass an exam, we say twenty five percent passed.
Converting between percentages, decimals, and fractions is essential. To convert a percentage to a decimal, divide by one hundred or move the decimal point two places left. To convert a decimal to a percentage, multiply by one hundred or move the decimal point two places right. Common fractions like one fourth, one half, and three fourths have easy percentage equivalents.
Now let's learn the essential percentage formulas. To find x percent of a number y, multiply y by x divided by one hundred. To find what percent x is of y, divide x by y and multiply by one hundred. For percentage increase or decrease, divide the change by the original value and multiply by one hundred. Let's see an example: twenty percent of one hundred fifty equals twenty divided by one hundred times one hundred fifty, which equals thirty.
Percentage increase and decrease problems are very common. The formula is: new value minus old value, divided by old value, times one hundred percent. If the result is positive, it's an increase. If negative, it's a decrease. For example, if a price goes from eighty dollars to one hundred dollars, that's a twenty five percent increase. If a score drops from ninety to seventy two, that's a twenty percent decrease.
To summarize your percentage preparation: Remember that percentage means per hundred. Master the conversions between percentages, decimals, and fractions. Use the key formulas for finding percentages and percentage changes. Always divide by the original value for percentage change calculations. Practice regularly with real-world problems to build confidence and speed.