Converting Fractions/Percentages/Decimals

Converting Fractions, Percentages, Decimals

We're going to look at how you convert from one number format to another

Percentage to Decimal (and Vice-Versa)

% to x.x and x.x to %

To Change from Percentage to Decimal we ..

• Divide by 100

• That's the same as moving the decimal point 2 places to the left (for example, 98.5% becomes 0.985, or 117% becomes 1.17)

• Quick tip - where percentages are less than 100, just put the numbers after the decimal point (for example 87% becomes 0.87)

• Let's try some

Multiple Choice

What is 17% as a decimal?

• 0.017

• 0.17

• 1.7

Open Ended

What is 65% as a decimal?

Open Ended

What is 111% as a decimal?

To Change from Decimal to Percentage we ..

• Multiply by 100 (and add the % symbol)

• That's the same as moving the decimal point 2 places to the right (for example, 0.17 becomes 17%

• For example, 0.026 becomes 2.6%

• Let's try some

Multiple Choice

What is 0.158 as a percentage?

• 1.58%

• 15.8%

• 158%

Multiple Choice

What is 2.78 as a percentage?

• 27.8%

• 278%

Open Ended

What is 1.0 as a Percentage?

Open Ended

What is 0.35 as a Percentage?

Fraction to Decimal (and Vice-Versa)

2/5 to x.x and x.x to 2/5

To Change from Fraction to Decimal we ..

• Divide the Top number (Numerator) by the Bottom number

• That will generate a decimal number (note: sometimes we may be asked to round our decimal answer to 1, 2 or 3 decimal places)

• To change 2/5 to a decimal we do 2 divided by 5 = 0.4

• Let's try some

Multiple Choice

What is 3/4 as a decimal?

• 0.25

• 0.34

• 0.5

• 0.75

Open Ended

What is 17/85 as a decimal?

CALCULATOR ALLOWED

Open Ended

What is 4/9 as a decimal (rounded to 2 decimal places)?

CALCULATOR ALLOWED

Open Ended

What is 33/60 as a decimal?

CALCULATOR ALLOWED

To Change from Decimal to Fraction to we ..

• Put the decimal number into a fraction over 1 (i.e. 0.7 becomes 0.7/1, or 0.65 becomes 0.65/1)

• Look at how many decimal places there are in the top number
  

• If one decimal place multiply both numbers by 10 (so 0.4/1 becomes 4/10)
  

• If two decimal places multiply both numbers by 100 (so 0.78/1 becomes 78/100)
  

• If three decimal places multiply both numbers by 1000 (so 0.179/1 becomes 179/1000)

Multiple Choice

What is 0.15 as a fraction?

• 1/5

• 15/10

• 15/100

Multiple Choice

What is 0.15 as a fraction (in its simplest form)?

• 15/100

• 3/20

Open Ended

What is 0.83 as a fraction?

Open Ended

What is 0.7 as a fraction in its simplest form?

Percentage to Fraction (and Vice-Versa)

25% to 1/4 and 1/4 to 25%

To Change from Percentage to Fraction we ..

• Simply put the % number over 100

• For example, 77% becomes 77/100

• For example 4% becomes 4/100

• Remember - we may be asked to show the fraction in its simplest form (i.e. 4/100 becomes 1/25)

Multiple Choice

What is 57% as a fraction?

• 57/1

• 57/10

• 57/100

Multiple Choice

What is 32% as a fraction in its simplest form?

• 16/50

• 32/100

• 8/25

Open Ended

What is 14% as a fraction in its simplest form?

Open Ended

What is 21% as a fraction?

To Change from Fraction to Percentage we ..

• Change to a Decimal (divide the top by the bottom)

• Multiply the decimal number by 100 and add the % symbol

• For example 3/8 becomes 0.375 which then becomes 37.5%

• Remember - we may be asked to round our answer to 1, 2 or 3 decimal places

Multiple Choice

What is 24/96 as a Percentage?

CALCULATOR ALLOWED

• 0.25%

• 2.5%

• 25%

Multiple Choice

What is 4/11 as a Percentage rounded to 2 decimal places

CALCULATOR ALLOWED

• 36.36%

• 36.37%

Open Ended

What is 7/15 as a Percentage rounded to 1 decimal place?

CALCULATOR ALLOWED

Open Ended

What is 27/48 as a Percentage?

CALCULATOR ALLOWED

Which is Bigger/Smaller?

Identify which number format has the biggest/smallest value

Multiple Choice

Which is bigger?

• 0.31

• 1/4

• 30%

Multiple Choice

Which is bigger?

• 2/5

• 38%

• 0.35

Multiple Choice

Which is smaller?

• 1/5

• 22%

• 0.17