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Fraction Fun Time!
I can add or subtract proper fractions and mixed
numbers with like denominators.
Essential Questions
• What is an improper fraction?
• How is an improper fraction changed into a
mixed number?
• How do I add and subtract fractions with
common denominators?
Improper Fractions
A fraction is an improper fraction when the
numerator is larger than the denominator.
When this happens that means that you have more
than one whole.
If the fraction is improper, then you need to change
the fraction into a mixed number.
Example: 23/5
How can we change an improper
fraction into a mixed number?
Remember NIDO?
Numerator on the inside!
Denominator on the outside!
Say we have the fraction 13/2,
6r1
Ready for some practice?
2 13
Of course you are!
-12
1
1
My mixed number is 6
2
SLATE TIME!!!!
Turn these improper fractions into mixed
numbers!
• 16/5
3 1/5
• 23/4
5 3/4
• 25/6
• 18/5
4 1/6
3 3/5
• 12/3
4
Changing ‘em back!
It’s easy to turn a mixed number
into an improper fraction again!
Take the denominator and multiply it
by the whole number!
5 2/7
7x5=35
Next, simply add the numerator!
35 + 2 = 37The denominator ALWAYS
37/7
stays the same!
Your Turn!
•7 3/5 38/ 5
4 1/4 17/4
• 8 2/3
26/
3
5 1/316/3
•6 1/4
25/4
3 1/2 7/2
Simplifying Fractions!
When we are adding or subtracting fractions,
we are NOT done until the fraction
is down to it’s simplest form!
What does that mean?
It means that the numerator
and denominator do not share a common factor!
The easiest way is to find the GCF
of both the numerator and denominator!
If you find the GCF, you will save
yourself time!
Let’s try it!
• Take the fraction 4/12
• Thumbs up when you have the GCF for
both!
• Did you say 4? That’s it!
• So divide the numerator and denominator
by the GCF.
• Your simplified fraction is 1/3.
Simplify It!
• Reduce these fractions to their simplest form. Your
work is not done until the numerator and denominator
DO NOT share a common factor!
• 12/18 2/3
4/32
1/8
• 22/42 11/21
10/ 45
2/9
• 18/24 3/4
8/56
1/7
• 12/60 1/5
5/20
1/4
Steps for adding fractions
• Take the fractions
•
and
2
7
10fractions together
If we want to ADD10
these two
we keep the denominator the same and then
add the numerators together.
•2+7=9
• The denominator stays the same and our new
numerator is 9.
• The new fraction is9
10
Partner Practice!
• Add these fractions together! Simplify if you
can! Also don’t forget, if the fraction turns out
to be IMPROPER, you MUST change it to a
MIXED NUMBER!
• 7/12 + 3/12 5/6
2/3+ 2/3
1 1/3
• 7/8 + 3/8 1 1/4
4/12 + 1
9/12
1/12
• 5/10 + 3/10 4/5
3/5 + 1/54/5
If you didn’t get them all correct, was it because
you forgot to simplify? YOU MUST!
Steps for subtracting
fractions
•
•
7
2
Take the fractions
and
8
8
Like adding fractions, when you SUBTRACT
fractions keep the denominator the same and
subtract the numerators.
•7-2=5
• The denominator stays the same and the
denominator is 8.
•
5
Our new fraction is
8
More Partner Practice!
• Subtract these fractions with common
denominators. SIMPLIFY, SIMPLIFY,
SIMPLIFY!!!
• 5/8 - 3/8
1/4
• 10/12 - 4/12 1/2
• 8/10 - 1/10 7/10
Steps for adding and
subtracting mixed numbers
• Change the mixed number into an improper
fraction.
• Then add or subtract the fraction.
• The denominator always stays the same.
• Add/subtract the numerator.
• Then turn the improper fraction back into a
mixed number.
Partner Practice Time!
2
+
6
5
+
3
2
9
6
9
4
5
2
5
3
-
-
1
7
3
3
5
4
5
4
8
6
8
Closure
• Explain to your shoulder partner how one
changes an improper fraction into a mixed
number and back.
• Then, give your partner step by step
directions on how to add and subtract
fractions.
• Thumbs up when you both have shared!
Independent Practice
• Change to a mixed number.
• 1. 16/3
2. 23/2
3. 43/8
4.
34/5
• Change to an improper fraction.
• 5. 5 1/2
3
+
5
4
9
8
9
6.
7 3/5
7.
2 2/3
9
-
6
8.
4
8
6
8
5 6/8