Percent of a Number Lesson 8 – 1

Vocabulary ‘ of ’ means to multiply

Need to Know : percents! # 1:Convert your percent. Percents must ALWAYS be converted to a decimal or fraction before you multiply or divide # 2:Percent ALWAYS out of 100. Remember, the work ‘per – cent’ means ‘out of 100’. # 3:Hint for decimal (move 2 places left) # 4:LABEL your answers!

How to solve? Example: 55% of 160 #1: change 55% to 0.55 #2: change of to ‘x’ #3: multiply: 0.55 x 160 #4: make sure decimal is in the correct place. Answer is 88.

How to solve? (2nd view) 0.45 Answer: What is 45% of $432? 432x

Practice Find each number. Round to the nearest hundredth, if necessary. 1)92% of 120 2)37.5% of 16 3)380% of $30 4)Five and a half percent of 60 5)You want to tip 15% and your bill is $120. How much will be your total with tip? $ $138

Percent and Estimation Lesson 8 – 3

Need to Know : estimation percents # 1:Round your percent. Round to the nearest 10%. Example: 54% becomes 50%. 68% becomes 70%. 12.5% becomes 10% # 2:Round the ‘of’ number. Round to the nearest whole, or tens place, or hundreds place. # 3:Find 10%. Then multiply by how many 10%’s you have.

How to solve? Example: 32% of 88 #1: change 32% to 30% #2: change 88 to 90 #3: 10% of 90 is 9. #4: multiply 9 x 3 and get 27. Your real answer will be close to 27.

Practice: mental math Estimate your answers 1)58% of 209 2)37.5% of 16 3)12% of 153 Special cases: 4)1.5% of 220 5)0.25% of or