Intro to Percent Workshop 2

Welcome to Intro to

Percent Workshop!

What are some examples of percent you see around you?

Learning Outcomes

At the end of the workshop, you will be able to...

• Understand the concept of percent and its relationship to fractions and decimals

• Convert between fractions, decimals and percentages

• Solve simple percentage calculations (of, is and what percent)

• Employ mental math techniques and shortcuts for quick and accurate percentage calculations

So what is a "per cent"?

A percent is a ________ expressed in hundredths!

​How can 25% be expressed as a ratio? Can this be expressed in any other way?

​A percent is based on a hundred and represents a portion of a whole.

​

Converting between

Fractions, Decimals, and Percentages

Multiple Choice

How do you express 29% as a fraction?

• $$\frac{29}{10}$$

• $$\frac{29}{100}$$

• $$\frac{100}{29}$$

• $$\frac{29}{1000}\text{}$$

Multiple Choice

How do you express 29% as a decimal?

• 0.29

• 0.029

• 2.9

• 29

Multiple Select

Choose the correct decimal and fraction form of 12%.

• $$\frac{12}{100}$$

• $$\frac{3}{25}$$

• $$\frac{6}{50}$$

• 0.12

• 0.012

Percent → Fraction/Decimal

___________ by ______

Move the decimal place _____ to the left

Decimal

Fraction*

*Ensure that the fraction answer is simplified when needed!

Multiple Choice

Express 8.7% as a decimal form.

• 0.87

• 8.7

• 0.087

• 0.0087

Multiple Select

Express $$\frac{3}{5}\%$$ as a decimal and fraction form.

• $$\frac{3}{500}$$

• $$\frac{300}{5}$$

• $$\frac{3}{5}$$

• 0.06

• 0.006

Fraction/Decimal → Percent

___________ by ______

Move the decimal place _____ to the _________

Decimal:

​Practice

Solving Simple Percentage Calculations

​Example: What is 18% of 300?

​Example: 54 is 18% of what number?

​Example: 54 is what percent of 300?

Multiple Choice

What is 7% of 52? Choose the correct expression.

• 52 ÷ 0.07

• 52 × 7

• 52 × 0.7

• 52 × 0.07

Multiple Choice

14% of what number is 80? Choose the correct expression.

• 80 × 1.4

• 80 × 0.14

• 80 ÷ 0.14

• 80 ÷ 14

Multiple Choice

93 is what percent of 9? Choose the correct expression.

• $$\frac{93}{9}$$

• $$\frac{93}{9}\times100$$

• $$\frac{9}{93}\times100$$

• 93 × 9

​The Triangle Method

​The percentage problems always involve three values:

1.

2.

3.

​

​Ex 1) 15 out of 50 is 30%

Ex 2) What is 31% of 140

Ex 3) 24% of what number is 80?

Percent Change

To find the percent change, what do you think you need to find first?

When two numbers that are being compared involve a change
whether it's an increase or decrease.

Example: The production of masks dropped 10% from last year.

The price of gas rose 5% over the last two years.

Percent Change

Formula:

​Remember: The change is compared or divided by the original value then multiplied by 100 to make it a percentage!

​Example: The price of a same pencil rose from $1.25 to $2.05. What is the percent change in the price of the pencil?

Any questions or feedback?

​

Thank you!