๐ฌ See a fraction fill the whole
The numerator counts selected equal parts; the denominator counts all equal parts.
๐ฏ By the end of this lesson...
You should be able to:
- Identify the numerator and denominator of a fraction.
- Recognise proper, improper and mixed fractions.
- Find equivalent fractions.
- Simplify fractions fully.
- Convert between mixed numbers and improper fractions.
- Compare and order fractions.
- Add and subtract fractions.
- Multiply and divide fractions.
- Solve real-life problems involving fractions.
๐ค Think About This...
Who ate the most?
Three friends share identical pizzas.
- Tariro eats ยฝ of a pizza.
- Rudo eats ยผ of a pizza.
- Tino eats โ of a pizza.
Who ate the greatest amount?
Looking only at the top or bottom number is not enough.
1๏ธโฃ What Is a Fraction?
A fraction represents a part of a whole or a part of a group.
The number of parts being considered.
The total number of equal parts.
2๏ธโฃ Types of Fractions
Proper Fraction
The numerator is smaller than the denominator.
Its value is less than 1.
Improper Fraction
The numerator is greater than or equal to the denominator.
Its value is at least 1.
Mixed Number
A whole number and a proper fraction written together.
Unit Fraction
A fraction with numerator 1.
3๏ธโฃ Equivalent Fractions
Equivalent fractions have the same value, even though they are written using different numbers.
We create an equivalent fraction by multiplying or dividing the numerator and denominator by the same non-zero number.
Example 1: Find an equivalent fraction for 3/5
Multiply both the numerator and denominator by 2.
โโโโโ
5 ร 2
4๏ธโฃ Simplifying Fractions
Simplifying a fraction means writing it using the smallest possible whole-number numerator and denominator.
We use the Highest Common Factor from Lesson 3.
Example 2: Simplify 18/24
Find the HCF of 18 and 24.
Divide both the numerator and denominator by 6.
โโโโโโ
24 รท 6
๐ง StudyNest Method: Simplifying Fractions
Step 2: Divide the numerator by the HCF.
Step 3: Divide the denominator by the same HCF.
Step 4: Check that the new numerator and denominator have no common factor other than 1.
5๏ธโฃ Improper Fractions and Mixed Numbers
Improper Fraction to Mixed Number
Example 3: Convert 11/4 to a mixed number
Divide the numerator by the denominator.
The whole-number answer becomes the whole part.
The remainder becomes the new numerator.
The denominator remains 4.
Mixed Number to Improper Fraction
Example 4: Convert 3 2/5 to an improper fraction
Multiply the whole number by the denominator.
Add the numerator.
Keep the same denominator.
๐ง StudyNest Conversion Methods
Improper โ Mixed
- Divide numerator by denominator.
- Write the quotient as the whole number.
- Use the remainder as the numerator.
- Keep the original denominator.
Mixed โ Improper
- Multiply whole number by denominator.
- Add the numerator.
- Place the answer over the original denominator.
6๏ธโฃ Comparing Fractions
The best comparison method depends on how the fractions are written.
Same Denominator
Example 5: Compare 3/8 and 5/8
The denominators are equal, so compare the numerators.
Different Denominators
Example 6: Compare 2/3 and 3/5
Find a common denominator.
๐ง StudyNest Method: Comparing Fractions
Step 2: If they are the same, compare the numerators.
Step 3: If the denominators differ, find a common denominator.
Step 4: Rewrite the fractions as equivalent fractions.
Step 5: Compare the new numerators.
7๏ธโฃ Adding Fractions
Fractions with the Same Denominator
Example 7
Add the numerators and keep the denominator.
Fractions with Different Denominators
Example 8
Find the LCM of 4 and 3.
Rewrite both fractions.
Add the numerators.
8๏ธโฃ Subtracting Fractions
Example 9
Find the LCM of 6 and 4.
The denominator names the size of the pieces and must first be made common.
๐ง StudyNest Method: Adding or Subtracting
Step 2: If they differ, find the LCM.
Step 3: Rewrite each fraction using the common denominator.
Step 4: Add or subtract the numerators.
Step 5: Keep the common denominator.
Step 6: Simplify the answer fully.
9๏ธโฃ Multiplying Fractions
To multiply fractions:
- multiply the numerators;
- multiply the denominators;
- simplify the answer.
Example 10
โโโโโ
3 ร 8
Simplify by dividing by 2.
โ๏ธ Cancelling Before Multiplying
We can simplify common factors before multiplying.
Example 11
Cancel common factors diagonally.
8 and 4 divide by 4
๐ Dividing Fractions
Dividing by a fraction is the same as multiplying by its reciprocal.
The reciprocal is found by exchanging the numerator and denominator.
Example 12
Keep the first fraction, change division to multiplication, and use the reciprocal of the second fraction.
Simplify.
๐ง StudyNest Method: Dividing Fractions
Step 2: Change the division sign to multiplication.
Step 3: Replace the second fraction with its reciprocal.
Step 4: Cancel common factors if possible.
Step 5: Multiply the fractions.
Step 6: Simplify the final answer.
1๏ธโฃ1๏ธโฃ Calculations with Mixed Numbers
Before multiplying or dividing mixed numbers, convert them to improper fractions.
Example 13
Convert both mixed numbers.
Cancel the common factor 3.
Convert to a mixed number.
๐ Real-Life Example: Baking
Example 14
One cake needs ยพ cup of sugar.
How much sugar is needed for 3 cakes?
๐ Real-Life Example: Fuel Remaining
Example 15
A vehicle begins a journey with a full tank.
It uses โ of the fuel in the morning and ยผ in the afternoon.
What fraction of the tank remains?
Find the total fraction used.
Subtract from one full tank.
๐ Real-Life Example: Time Spent Studying
Example 16
Nyasha spends:
- โ of an hour revising Mathematics;
- ยผ of an hour revising Science.
How much time does she spend studying altogether?
Convert the fraction of an hour into minutes.
๐ง The StudyNest Fraction Strategy
Step 2: Check whether mixed numbers must first be converted.
Step 3: For addition or subtraction, check the denominators.
Step 4: For multiplication, multiply across and cancel where possible.
Step 5: For division, multiply by the reciprocal of the second fraction.
Step 6: Simplify the final answer.
Step 7: Convert to a mixed number if the question requires it.
Step 8: Check whether the answer makes sense in context.
๐ฏ Exam Tips
โ Common Mistakes
Adding both the numerators and denominators.
For example, 1/3 + 1/4 is not 2/7.
Using a common denominator but forgetting to change the numerator.
Forgetting to simplify the final answer.
Adding the whole numbers and fractions separately without checking whether regrouping is needed.
Taking the reciprocal of the first fraction instead of the second when dividing.
Multiplying mixed numbers before converting them to improper fractions.
Cancelling terms across addition or subtraction.
Cancelling applies to factors in multiplication, not separate terms being added.
๐ฎ Your Turn!
- Identify the numerator and denominator of 7/12.
- State whether 5/8 is proper, improper or mixed.
- State whether 11/6 is proper, improper or mixed.
- Simplify 20/30.
- Convert 13/5 to a mixed number.
- Convert 2 3/7 to an improper fraction.
- Which is greater: 5/6 or 7/9?
- Calculate 3/8 + 1/4.
- Calculate 7/10 โ 1/5.
- Calculate 4/9 ร 3/8.
- Calculate 5/6 รท 10/9.
- Calculate 1 ยฝ + 2 ยผ.
- Calculate 2 โ ร 1 ยฝ.
- A water tank is 5/6 full. During the day, 1/4 of the full tank is used. What fraction of the tank remains?
- A recipe uses 2/3 cup of flour for one loaf. How much flour is required for 4 loaves?
โ Show Answers
- Numerator = 7, denominator = 12
- Proper fraction
- Improper fraction
- 20/30 = 2/3
- 13/5 = 2 3/5
- 2 3/7 = 17/7
-
5/6 = 15/18 and 7/9 = 14/18
Therefore, 5/6 is greater. - 3/8 + 2/8 = 5/8
- 7/10 โ 2/10 = 1/2
- 4/9 ร 3/8 = 12/72 = 1/6
- 5/6 ร 9/10 = 45/60 = 3/4
- 1 2/4 + 2 1/4 = 3 3/4
- 7/3 ร 3/2 = 7/2 = 3 1/2
-
5/6 โ 1/4
= 10/12 โ 3/12
= 7/12 - 4 ร 2/3 = 8/3 = 2 2/3 cups
๐ง Remember This
Simplify using the HCF.
Add and subtract only after making denominators equal.
Multiply numerators together and denominators together.
To divide fractions, multiply by the reciprocal of the second fraction.
Always simplify your final answer.
๐ฏ Before Moving On...
- โ Can I identify the numerator and denominator?
- โ Can I recognise proper, improper and mixed fractions?
- โ Can I find equivalent fractions?
- โ Can I simplify a fraction fully?
- โ Can I convert between mixed numbers and improper fractions?
- โ Can I compare fractions?
- โ Can I add and subtract fractions?
- โ Can I multiply and divide fractions?
- โ Can I solve a word problem involving fractions?
๐ Well Done!
You can now understand, compare and calculate confidently with fractions.
Identify the operation โ Choose the correct fraction method โ Simplify the answer
๐ Your Progress
Lesson 6 of 17