Converting Decimals to Fractions and Fractions to
Decimals and then to Percents
Use these websites to fill in the blanks:
1. http://www.mathsisfun.com/converting-fractions-decimals.html
Convert Fractions to Decimals
The simplest method is to use a calculator.
Just divide ___________________ of the fraction by the
_______________, and read off the answer !
Example: What is 5/8 as a fraction?
... get your calculator and type in "5 / 8 =", the answer should be
0.625
To convert a Fraction to a Decimal manually, follow these steps:
Step 1: Find a number you can multiply by _________________________ to make it
10, or 100, or 1000, or any 1 followed by 0s.
Step 2:
_________________________________________________________________________
Step 3. Then write down _________________________, putting the decimal place in the
____________________ (one space from the right for every zero in the bottom number)
Example 1: Express 3/4 as a Decimal
Step 1: We can mulitply 4 by
25 to become 100
Step 2: Multiply top and bottom by 25:
Step 3: Write down 75 with the decimal place 2 spaces from the right (because 100 has 2
zeros);
Example 2: Express 3/16 as a Decimal
Step 1: We have to mulitply 16 by 625 to become 10,000
Step 2: Multiply top and bottom by 625:
Step 3: Write down 1875 with the decimal place 4 spaces from the right (because 10,000
has 4 zeros);
Example 2: Express 1/3 as a Decimal
Step 1: There is no way to multiply 3 to become 10 or 100 or any power of 10, but we can
calculate an ______________________ decimal by choosing to multiply by, say, 333
Step 2: Multiply top and bottom by 333:
Step 3: Now, 999 is nearly 1,000, so let us write down 333 with the decimal place 3 spaces
from the right (because 1,000 has 3 zeros):
___________________ (accurate to only 3 decimal places !!)
2. http://www.mathsisfun.com/converting-decimals-fractions.html
Convert Decimals to Fractions
To convert a Decimal to a Fraction follow these steps:
Step 1: Write down the decimal divided by 1.
Step 2: Multiply both top and bottom by 10 for
________________________________________________________________.
(For example, if there are two numbers after the decimal, then use 100, if there
are three then use 1000, etc.)
Step 3: Simplify (or reduce) the fraction
Example 1: Express 0.75 as a fraction
Step 1: Write down:
_____________________________
Step 2: Multiply both top and bottom by 100 (because there were 2 digits after the decimal
place):
(Do you see how it neatly turns the top number
into a whole number?)
Step 3: Simplify the fraction:
Answer = 3/4
Note: 75/100 is called a decimal fraction and 3/4 is called a common fraction !
Example 2: Express 0.625 as a fraction
Step 1: write down:
Step 2: multiply both top and bottom by 1,000 (there were 3 digits after the decimal place
so that is 10×10×10=1,000)
625
1,000
Step 3: Simplify the fraction (it took me two steps here):
Answer = 5/8
Example 3: Express 0.333 as a fraction
Step 1: Write down:
___________________
Step 2: Multiply both top and bottom by 1,000 (there were 3 digits after the decimal place
so that is 10×10×10=1,000)
_______________
Step 3: Simplify Fraction:
__________________
Answer = 333/1,000
3. http://www.mathsisfun.com/decimal-fraction-percentage.html
Decimals, Fractions and Percentages
Decimals, Fractions and Percentages are just different ways of showing the same
value:
A Half can be written...
As a fraction:
_______
As a decimal:
____
As a percentage:
____
A Quarter can be written...
As a fraction:
/4
1
As a decimal:
0.25
As a percentage:
25%
Converting Between Percentage and Decimal
Percentage means ____________, so 50% means 50 per 100, or simply
50 by 100 you get 0.5 (a decimal number). So:
/100. If you divide
50
•
__________________________________________________________________
•
__________________________________________________________________
•
To convert from decimal to percentage: multiply by 100 (and add a "%" sign).
The easiest way to multiply (or divide) by 100 is to ____________________________.
So:
From Decimal
To Percent
move the decimal point
_______________________,
and add the "%" sign.
... or ...
From Percent
To Decimal
move the decimal point
_______________________,
and remove the "%" sign.
Converting Between Fractions and Decimals
The easiest way to convert a fraction to a decimal is to
_____________________________________________________________________
(divide the numerator by the denominator in mathematical language)
Example: Convert 2/5 to a decimal
Divide 2 by 5: ______________________________________
Answer: 2/5 = 0.4
To convert a decimal to a fraction needs a little more work:
Steps
First, write down the decimal "over" the number 1
Then multiply top and bottom by 10 for every number after
the decimal point (10 for 1 number, 100 for 2 numbers, etc)
Example
(This makes it a correctly formed fraction)
Then Simplify the fraction
Converting Between Percentages and Fractions
The easiest way to convert a fraction to a percentage is to divide the top number by the
bottom number. ____________________________________________ (and add the "%"
sign)
Example: Convert 3/8 to a percentage
First divide 3 by 8: 3 ÷ 8 = 0.375,
Then multiply by 100: ______________________________
Add the "%" sign: 37.5%
Answer: 3/8 = 37.5%
To convert a percentage to a fraction, first _________________ (divide by 100), then use
the steps for converting decimal to fractions.