Let's build a strong foundation for working with fractions!
What we'll learn:
✓ What fractions represent
✓ Parts of a fraction
✓ Fractions in real life
✓ Adding fractions with common denominators
✓ Introduction to unlike denominators
A fraction is a way to represent a part of a whole.
If you have a whole pizza cut into 8 slices and you eat 3 slices, you've eaten 3 out of 8 pieces.
We write this as: 3/8
Fraction: A number that represents a part of a whole.
Fractions show us equal parts of something.
• This tells us how many parts we have
• It's the number of parts we're talking about
• This tells us how many equal parts make up the whole
• It's the total number of pieces
Numerator: The top number - how many parts we have
Denominator: The bottom number - how many equal parts in the whole
Numerator = North
North is UP, so the numerator goes on top!
Denominator = Down
Down is below, so the denominator goes on the bottom!
Denominator = Down
Both start with D!
2/5 means 2 out of 5 equal parts
2 parts are shaded (numerator)
5 total equal parts (denominator)
The denominator (5) tells us the whole is divided into 5 equal pieces.
The numerator (2) tells us we're looking at 2 of those pieces.
3/4 means 3 out of 4 equal parts
3 parts are shaded (numerator)
4 total equal parts (denominator)
If you have 4 cookies and you eat 3 of them, you ate 3/4 of the cookies!
Your Task:
Key Point: All the parts must be equal in size!
These 3 parts are EQUAL, so this shows 2/3
These parts are NOT equal!
For something to be a fraction, all the parts must be EQUAL in size.
• Eating 2/8 of a pizza
• Drinking 1/2 of your milk
• Sharing 1/4 of a candy bar
• A quarter of an hour = 1/4 hour = 15 minutes
• Half past two = 1/2 hour past 2:00
• A quarter = 1/4 of a dollar
• A dime = 1/10 of a dollar
• 1/2 inch, 3/4 cup, 2/3 mile
Look at this shape:
What fraction is shaded?
Answer: 4/6
Why?
• There are 6 equal parts total (denominator)
• 4 parts are shaded (numerator)
• So the fraction is 4/6
Sarah has 8 markers. 5 of them are red.
What fraction of her markers are red?
Answer: 5/8
Why?
• The total number of markers is 8 (denominator)
• The number of red markers is 5 (numerator)
• So 5/8 of the markers are red
Your Task:
Think: What does the denominator tell you about how many cubes to use?
1/2 of a pizza is NOT the same amount as 1/2 of a cookie!
Why? Because the whole is different.
1/2 of a large circle:
1/2 of a small circle:
Both are 1/2, but the amounts are different because the wholes are different!
3/3 = 1
5/5 = 1
8/8 = 1
Why does 4/4 = 1?
All 4 parts are included - that's the whole thing!
When the numerator and denominator are the same, the fraction equals 1 whole.
5/4 is more than 1 whole
This is called an improper fraction.
What does 5/4 look like?
One whole (4/4) plus one more fourth (1/4) = 5/4
To add fractions with the SAME denominator:
1. Keep the denominator the same
2. Add the numerators
3. Write the sum over the same denominator
If you have 2 slices of pizza out of 8 slices, and someone gives you 3 more slices, you now have 5 slices out of 8.
2/8 + 3/8 = 5/8
The denominator stays 8 because the pizza is still cut into 8 slices!
1/5 + 2/5 = ?
Start with 1/5:
Add 2/5 more:
= 3/5
We added the numerators: 1 + 2 = 3
We kept the denominator: 5
Problem 1: 2/7 + 3/7 = ?
Solution:
Step 1: Check the denominators - they're both 7 ✓
Step 2: Add the numerators: 2 + 3 = 5
Step 3: Keep the denominator: 7
Answer: 5/7
Problem 2: 1/6 + 4/6 = ?
Solution:
Step 1: Check the denominators - they're both 6 ✓
Step 2: Add the numerators: 1 + 4 = 5
Step 3: Keep the denominator: 6
Answer: 5/6
Problem 3: 3/10 + 2/10 = ?
Solution:
Step 1: Check the denominators - they're both 10 ✓
Step 2: Add the numerators: 3 + 2 = 5
Step 3: Keep the denominator: 10
Answer: 5/10
Problem 4: 2/8 + 5/8 = ?
Solution:
Step 1: Check the denominators - they're both 8 ✓
Step 2: Add the numerators: 2 + 5 = 7
Step 3: Keep the denominator: 8
Answer: 7/8
Problem 5: 1/12 + 7/12 = ?
Solution:
Step 1: Check the denominators - they're both 12 ✓
Step 2: Add the numerators: 1 + 7 = 8
Step 3: Keep the denominator: 12
Answer: 8/12
Problem 6: 4/9 + 2/9 = ?
Solution:
Step 1: Check the denominators - they're both 9 ✓
Step 2: Add the numerators: 4 + 2 = 6
Step 3: Keep the denominator: 9
Answer: 6/9
To subtract fractions with the SAME denominator:
1. Keep the denominator the same
2. Subtract the numerators
3. Write the difference over the same denominator
5/8 - 2/8 = ?
• The denominators are the same (8), so we can subtract
• Subtract the numerators: 5 - 2 = 3
• Keep the denominator: 8
5/8 - 2/8 = 3/8
4/6 - 2/6 = ?
Start with 4/6:
Take away 2/6:
= 2/6
Problem 1: 5/7 - 2/7 = ?
Solution:
Subtract the numerators: 5 - 2 = 3
Keep the denominator: 7
Answer: 3/7
Problem 2: 7/10 - 3/10 = ?
Solution:
Subtract the numerators: 7 - 3 = 4
Keep the denominator: 10
Answer: 4/10
Problem 3: 8/12 - 5/12 = ?
Solution:
Subtract the numerators: 8 - 5 = 3
Keep the denominator: 12
Answer: 3/12
Problem 4: 6/8 - 1/8 = ?
Solution:
Subtract the numerators: 6 - 1 = 5
Keep the denominator: 8
Answer: 5/8
Can we add 1/2 + 1/3?
The denominators are different (2 and 3).
1/2 looks like this:
1/3 looks like this:
We can't just add the numerators! The pieces are different sizes.
It's like trying to add apples and oranges.
To add fractions with DIFFERENT denominators:
1. Find a common denominator (a number both denominators divide into)
2. Convert both fractions to have that common denominator
3. Then add the numerators
4. Keep the common denominator
For now, just know that we need to make the denominators match before we can add or subtract.
This is a sneak peek of what's coming in our next lessons!
Step 1: Notice that 4 can be divided by 2, so let's use 4 as our common denominator.
Step 2: Convert 1/2 to fourths:
1/2 = 2/4 (we multiply top and bottom by 2)
Step 3: Now we can add:
2/4 + 1/4 = 3/4
The answer is 3/4!
Your Task:
Examples to look for:
Challenge: Can you find a situation where you could add two fractions?
What is the bottom number of a fraction called?
Correct Answer: B) Denominator
The denominator is the bottom number that tells us how many equal parts make up the whole.
Look at this shape:
What fraction is shaded?
Correct Answer: B) 3/5
There are 5 total equal parts (denominator = 5) and 3 are shaded (numerator = 3).
Solve: 3/8 + 2/8 = ?
Correct Answer: B) 5/8
When adding fractions with the same denominator, add the numerators (3 + 2 = 5) and keep the denominator (8).
What does 4/4 equal?
Correct Answer: B) 1
When the numerator and denominator are equal, the fraction equals 1 whole because all parts are included.
Solve: 7/10 - 3/10 = ?
Correct Answer: C) 4/10
When subtracting fractions with the same denominator, subtract the numerators (7 - 3 = 4) and keep the denominator (10).
Before adding 1/3 + 1/4, what must you do first?
Correct Answer: C) Find a common denominator
When fractions have different denominators, you must first convert them to have the same denominator before adding.
What you learned today:
✓ What fractions represent (parts of a whole)
✓ Numerator (top) and Denominator (bottom)
✓ All parts must be EQUAL
✓ Adding fractions with common denominators
✓ Subtracting fractions with common denominators
✓ Introduction to unlike denominators
Coming Soon:
Finding common denominators
Simplifying fractions
Multiplying & dividing fractions
Keep up the great work! 🌟