Percent

Learning goal LG: Demonstrate an understanding of percent concretely, pictorially and symbolically. Kid Friendly: Show that you can read and write percent and draw it What I think I know: Where do you see percents being used in the real world?

Definition History of the word: In Latin the term cent means hundred. So per cent literally means per hundred Definition: Percent means out of one hundred Percents can be as low as 0 and can go higher than 100 A percent sign looks like this %

Easy way to see percent The easiest way to see percent is when it is on something out of one hundred 50 out of the 100 25 out of the 100 boxes are shaded. boxes are shaded. This would mean This would mean 50 % are shaded. 25 % are shaded.

Task #1 Using graph paper set up (minimum) four 100s grids Color in any amount you want Write the percentage of squares that are colored in. Write the percentage of squares NOT colored in. These two numbers should add up to 100

Converting percentages to fractions Changing from percent to fractions to decimals to ratios is quite easy! If you have a percent first, then you take that number and make it out of 100. See: 25% = 25/100 4% = 4/100 99% = 99/100

Converting percentages to decimals Using those same examples, we can turn them into decimals. 25% = 25/100 which means it is twenty five hundredths. We know that to write that as a decimal it looks like this 0.25 Right? Easy! So then 4% = 4/100 which is four hundredths which looks like 0.04 Then 99% = 99/100 = 0.99

Converting decimals into percentages To turn a decimal into a percentage you take the decimal and multiply it by 100 So 0.05 multiplied by 100 (or moving the decimal over to the right two places) is 5 which means it is 5% 0.50 multiplied by 100 is 50 so it equals 50%

Converting percentages to decimals Changing a percentage to a decimal is just the opposite of changing a decimal to a percentage Instead of multiplying by 100 like you had to do, you do the opposite! You are going to divide the number by 100 This would look like this: 60% divided by 100 (as in moving the decimal point two spots to the left) is 0.60 1% divided by 100 is 0.01

Converting fractions to percentages Changing a fraction to a percentage just means you need to make the fraction out of 100 For example, if you have the fraction 20/50 you need to make the bottom number 100 To do this you would need to multiply 50 by 2. This means you would also have to multiply the top number, 20, by 2 Your new fraction would be 40/100. Once you have the fraction over 100 you can just write the top number as a percentage. So 40/100 = 40%

Task #2 Even though percent means out of 100, you can still find a percentage out of any number It is easiest when the number goes evenly into 100. Numbers that go into 100 evenly (as in the factors of 100) are: 1, 2, 4, 5, 10, 20, 25, 50, 100 Using graph paper set up four new grids. Each grid must be a different number from each other and must be a factor of 100. Color in some of the squares. How could you find the percentage of what you have colored in? (*hint: equivalent fractions!)

Think of money… When you have three quarters what fraction and percentage out of a dollar do you have?