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Math 6. FINDING PERCENT OF A NUMBER. Objective:. Use a percent to find a part of a whole. A ratio is a comparison of 2 quantities using division. Any number that can be expressed as a ratio is called a rational number. Quick Review…. So what numbers are rational? All fractions
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Math 6 FINDING PERCENT OF A NUMBER
Objective: • Use a percent to find a part of a whole.
A ratio is a comparison of 2 quantities using division. Any number that can be expressed as a ratio is called a rational number. Quick Review…
So what numbers are rational? • All fractions • All whole numbers • All terminating decimals • All repeating decimals
How can a number be expressed as a ratio? • All fractions are ratios.
To write a whole number as a ratio, divide it by 1. • Example:
A terminating decimal can be written as a fraction. • Example: • 0.8362= • A decimal is ‘named’ after the smallest place it occupies.
A repeating decimal is a rational number. • It can be expressed as a ratio. • http://www.youtube.com/watch?v=jVzjopXPMIc
A percent is a ratio of a number to 100. This symbol: % indicates a percent. For example, 40% is the ratio 40 to 100, or .
Write Percents as Fractions Write 35% as a fraction in simplest form. 35% = = Write the percent as a fraction with a denominator of 100. Simplify.
Writing Percents as Decimals Write 43% as a decimal. 43% = = 0.43 Write the percent as a fraction with a denominator of 100. Write the fraction as a decimal.
Writing Percents as Decimals Write 43% as a decimal. 43% = = 0.43 Since 43% means 43/100, divide by 100 to convert to a decimal. (Move the decimal point two places to the left.)
Key Point: In any word problem, when you see the word ‘of’ it generally means you must multiply.
Key Point: To multiply by a percent, first convert it to a decimal then multiply.
To find the percent of a number, convert the percent to a decimal, then multiply the two numbers.
Guided Practice
Guided Practice Find 3% of 12. Find 12.5% of 56. Find 150% of 17.
Guided Practice The regular price of a calculator is $15.40. It is on sale for 30% off the regular price. What is the sale price?
Assignments 1-Finding Percents of a Number (A) 2-M6 HW Percentage Word Problems
When finding percent of a number, simply multiply the decimal equivalent by the number. You may have to complete another step, such as subtraction, to solve a discount price question. In order to be competent in math, you must UNDERSTAND and be able to COMMUNICATE your answer. Conclusion