1at 5.4 percentages

1at 5.4 percentages

lesson goals:

• I know what percentages are

• I can calculate a percentage of a total

• I can calculate a percentage

Who's done with their homework?

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Percentages

• per cent > per 100 (think of french)

• 5% means 5 out of a 100

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Percentages and multiplication factor

• 100% = 1

• 50% = 0,50

• 20% = 0,20

• 7% = 0,07

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• How do you find the multiplication factor from a percentage?

Multiple Choice

17% is...

• 17

• 0,17

• 1,7

• 1,17

Multiple Choice

7,5% =

• 0,75

• 7,5

• 0,075

• 1,75

The percentage of a total

• What is 45% of 75?

• 45% = 0,45

• 0,45 x 75 = 33,75

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  So: multiply the multiplication factor by the total.

What percentage is 42 of 358?

• 42 / 358 x 100% = 11,73184.... = 11.7%

• Don't use the % sign on your calculator!

• Always round percentages to 1 decimal place.

Homework

• Make 5.4 and 5.5 this week.

• On friday I'll explain 5.5

• Make your exercises online

• you can find your homework in magister.me > chapter 5 > week 2

• Don't forget to check it off in magister.me when you finished a paragraph!