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There are different ways to write rational numbers. Each is useful in different situations. It is also possible to convert between these forms of numbers. This lesson will focus on exploring such number forms and converting them into each other.

Catch-Up and Review

Here are a few recommended readings before getting started with this lesson.

Explore

A Different Way of Writing Improper Fractions

Consider two bars split into into an equal number of parts. Try to determine the fraction that the bars represent.
A bar split into different number of parts is randomly generated
Notice that the first bar is always fully shaded. This indicates that an improper fraction represents the shown diagram each time. Also, the first bar can be represented by a fraction, whose numerator and denominator are the same. Its value is always
A bar split into different number of parts is randomly generated
The fraction on the right-hand side can be represented by a proper fraction. Together, and a proper fraction form a new way of writing the value of an improper fraction.
Discussion

Mixed Numbers

A mixed number consists of a non-zero integer number and a proper fraction.

The following are examples of mixed numbers.
Consider the graphic representation of different mixed numbers.
An applet that illustrates different mixed numbers
Mixed numbers represent the rational numbers between any two integers.
Discussion

Converting a Mixed Number Into an Improper Fraction

Improper fractions and mixed numbers are two different ways of writing numbers that can have the same value. Sometimes, it is useful to convert between them. Consider the following mixed number.
This mixed number can be rewritten as an improper fraction in three steps.
1
Multiply the Integer Part by the Denominator
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First, identify the integer part of the mixed number. This is the integer number written before the fraction.

5 is the integer part of the mixed number 5 and 2/9
Next, multiply the integer part by the denominator of the fraction. In this case, the denominator of the fraction is
2
Add the Numerator
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Add the numerator of the fraction to the number from the previous step. In the given mixed number, the numerator of the fraction is
This is the numerator of the improper fraction.
3
Write the Denominator
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Write the numerator of the fraction part as the denominator of the improper fraction. The denominator in the fraction of the given mixed number is Therefore, this is also the denominator of the improper fraction.

Extra

Interact With an Applet that Converts Different Mixed Numbers Into Improper Fractions
Submit the values of the integer part, numerator and denominator between and inclusively. Then, the process of converting the mixed number into an improper fraction will be illustrated.
Mixed number is rewritten as a fraction
Example

Looking for the First Clue

Izabella's older sister Tiffaniqua wanted to encourage her to practice converting between mixed numbers and fractions. She came up with an idea to leave some clues for Tiffaniqua all over their house leading to a hidden present. She told Izabella to start at the door of Izabella's room.
Text on the note:'4 and 1/3=x/y, 6 and 3/8=z/w; 1. Take x+y steps to my room. 2. Turn left and take z-2w steps.
Izabella sprang up, running to her door she opened it quickly. She found the first clue. It asks her to rewrite two mixed numbers as fractions. Doing that will help her decode the directions to the hidden present.
a
b
b How many steps should Izabella take in the direction of Tiffaniqua's room? How many steps should Izabella take after turning left? Write each answer in list form.

Hint

a Multiply the integer part by the denominator of the fractional part and add the numerator to find the numerator of the improper fraction.
b The denominator of the improper fraction is the same as the denominator of the fraction in the mixed number.
c Identify the values of and by comparing the fractions.

Solution

a The first mixed number that should be rewritten is Start by multiplying the part by the of the fraction. Then, add the of the fraction. The result is the numerator of the improper fraction.
The numerator of the improper fraction is
The denominator of this fraction is the same as the denominator of the fraction in the mixed number. This means that it is
b The second mixed number, can be rewritten as an improper fraction by following the same method. First, multiply its integer part by the denominator and add the numerator.
The numerator of the improper fraction is
The denominator is equal to the denominator of the fraction in the mixed number.
c Each question will be answered one at a time.

First Question

In the note, the numerator of the first improper fraction is and the denominator is
This means that and The first instruction that Izabella received is the following.
Add the known values of and to find how many steps in the direction of Tiffaniqua's room Izabella should take.

Second Question

The numerator of the second improper fraction is and the denominator is
This means that and Now, consider the second instruction.
Substitute the values of and and evaluate the expression.
Izabella should take steps after turning left.
Discussion

Converting an Improper Fraction Into a Mixed Number

Converting an improper fraction into a mixed number can help to estimate the actual value of the fraction. Consider the following improper fraction.
This improper fraction can be rewritten as a mixed number in three steps.
1
Divide the Numerator by the Denominator
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Start by dividing the numerator of the improper fraction by the denominator. Note that the quotient must be an integer number.
Applet to compute the division of two numbers, 21 and 4
Here, the result of the division of by is the quotient of with a reminder of
2
Write the Integer Part
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Recall that a mixed number consists of an integer part and a proper fraction. The integer part is equal to the quotient of the improper fraction. In this case, it is

Mixed number with the integer of 5 and an unknown proper fraction
3
Write the Fraction Part
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Now the numerator and denominator of the fraction part will be identified. The numerator is equal to the remainder of the division from the first step. In this case, the reminder is and becomes the numerator of the fraction part.

Mixed number with the integer of 5 and the proper fraction with the numerator of 1

Note that the numerator must be less than the denominator since the fraction part of a mixed number is a proper fraction. The denominator is the same as the denominator of the improper fraction. Therefore, its value is

Mixed number with the integer of 5 and the proper fraction of 1 over 4

The numerator is less than the denominator, so the fraction is indeed a proper fraction. Finally, finding the mixed number corresponding to is complete.

Example

A Clue Hidden in the Office Room

Izabella completed the instructions from the first clue and she ended up in her dad's home office. Looking through piles of papers, she finally found the second clue in the book shelf.
The office room where the clue is hidden among the books on the bookshelf
External credits: @gstudioimagen
To find the numbers of steps she needs to take, Izabella needs to rewrite the improper fractions as mixed numbers.
a
b

Hint

a Divide the numerator by the denominator by using the long division.
b The quotient of the division of and represents the integer part of the corresponding mixed number.

Solution

a Izabella needs to rewrite as a mixed number. This requires dividing the numerator by the denominator. Long division can be applied here.
Applet to compute the division of two numbers, 87 and 5
The quotient is with a reminder of Recall that the quotient represents the integer part of the corresponding mixed number. The remainder represents the numerator of the fraction in the mixed number. The denominator is the same as the denominator of improper fraction.
The calculations show that Izabella needs to take steps to the right after leaving the office room.
b This time, Izabella needs to rewrite as an improper fraction. Again, divide by using long division.
Applet to compute the division of two numbers, 115 and 9
The quotient is with a reminder of The quotient represents the integer part and the reminder represents the numerator of the fraction in the mixed number. The denominator is equal to the denominator of improper fraction.
According to the second instruction, Izabella should turn right and take steps. Where will she end up?
Pop Quiz

Converting Between Mixed Numbers and Improper Fractions

Convert the given mixed number into the corresponding improper fraction or the other way around — the given improper fraction into a mixed number. If the improper fraction corresponds to an integer number, leave the fraction fields empty. Do not simplify the fraction part in a mixed number.

A random generator that generates improper fractions or mixed numbers
Discussion

Introducing Decimal Numbers

While mixed numbers help estimate the value of an improper fraction, they are not very convenient in calculations. For that reason, the equivalent number to the fraction of a mixed number can be written after the integer followed by a dot.
This observation leads to the definition of decimal numbers.
Concept

Decimal Numbers

Numbers that lie between integers on the number line can be written as decimal numbers. These consist of an integer part, a decimal point as a separator, and a non-zero decimal part written to the right of the decimal point. Consider the number as an example.
The decimal 12.346 where 12 is an integer part, . is a decimal point, and 346 is a decimal part
The integer part of this number is Since there is a decimal part, the number is greater than but less than Therefore, when plotting on a number line, the point will lie between and
Discussion

Converting a Decimal Number Into a Fraction

It is possible to convert a decimal number into a fraction and the other way around. Consider the following decimal number.
A decimal number can be rewritten as a fraction in three steps.
1
Count the Number of Decimal Places
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The number can be read as hundredths. There are two decimal places.

0.56 has two decimal places
2
Write as a Fraction With the Denominator of
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The number has decimal places. This means that can be written it as a fraction with a numerator of and with a denominator of
3
Simplify the Fraction
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Next, check whether can be simplified. Start by splittting the numerator and denominator into prime factors.
The numbers share two common factors. Their product is the GCF of and
Finally, divide both the numerator and denominator by
The fractions and are equivalent and they both correspond to the decimal

Extra

Interact With an Applet That Converts Decimals to Fractions
Submit a decimal number between and with no more than digits after the decimal point. Then, the process of converting that decimal into a fraction will be shown.
The submitted decimal is converted to a fraction
Example

A Clue Among the Kitchen Supplies

After successfully finding the second clue and following the instructions, Izabella ended up in the kitchen. She started looking for the third clue.
The kitchen with the clue hidden
External credits: @upklyak
She found the clue over the oven vent. The instructions said to rewrite a decimal number as a fraction in the simplest form.
a
b
c How many steps in total should Izabella take?