IB MYP 3 2021 Edition
4.01 Percentages on the calculator
Lesson

It's important to consider whether the answer is reasonable every time you use your calculator, although calculators are very smart, they just do what you tell them. They won't necessarily pick up on mistakes.

Like entering a mixed fraction on a calculator, entering a percentage on a calculator is also a second function.

You'll have to find the tiny $%$% sign above one of the buttons. Sometimes it's above the $=$= sign but not always, as shown in red in the picture above. It just depends on your calculator. However, again we will need to use the shift button to use the second function.

If your calculator does not have a % button, you can always convert the number into a percentage by dividing by $100$100.  For example, if you need to use $23%$23%, but you don't have a percent button, you can type in $23\div100$23÷​100 on the calculator.

#### Practice questions

##### Question 1

Using a calculator, convert $10%$10% to a decimal.

##### Question 2

We want to compare the numbers $\frac{1}{4}$14, $80%$80% and $0.7$0.7.

1. First, convert $\frac{1}{4}$14 into a percentage using a calculator, writing it as a mixed number if needed.

2. Now convert $0.7$0.7 into a percentage using the calculator.

3. Which of the following arranges $\frac{1}{4}$14, $80%$80% and $0.7$0.7 from largest to smallest?

$\frac{1}{4}$14, $80%$80%, $0.7$0.7

A

$80%$80%, $0.7$0.7, $\frac{1}{4}$14

B

$0.7$0.7, $\frac{1}{4}$14, $80%$80%

C

$80%$80%, $\frac{1}{4}$14, $0.7$0.7

D

$\frac{1}{4}$14, $80%$80%, $0.7$0.7

A

$80%$80%, $0.7$0.7, $\frac{1}{4}$14

B

$0.7$0.7, $\frac{1}{4}$14, $80%$80%

C

$80%$80%, $\frac{1}{4}$14, $0.7$0.7

D

##### Question 3

Consider the statement:

$\frac{67}{50}$6750 > $154%$154%

1. Using a calculator, convert $\frac{67}{50}$6750 to a percentage

2. Hence, is the statement True or False?

True

A

False

B

True

A

False

B