Definitions
Keep Change Flip
Dividing Two Fractions
Dividing Mixed Numbers
Miscellaneous
Methods
Methods
100
The rule (three words) used when dividing fractions?
KEEP CHANGE FLIP!
100
If you are dividing a whole number by a fraction you must first do what to the whole number?
example: 25 = what fraction?
Put a 1 underneath it to make it a fraction.
25/1
100
1/2 ÷ 1/3
3/2 = 1 1/2
100
1 1/2 ÷ 2 3/4
3/2 x 4/11 = 12/22 = 6/11
100
THIS is the Greatest Common Factor (GCF) we can use to make the problem easier (when 'Cross Simplifying')
5/8 ÷ 3/4 =
5/8 x 4/3
4
200
A (Proper or Improper) Fraction is (Less or More) than one. The numerator is smaller than the denominator.
Example: 2/5
Proper Fraction
200
When dividing fractions, what do you do to the first fraction in the problem?
KEEP it the same.
200
3/4 ÷ 2/5
15/8 = 1 7/8
200
2 2/5 ÷ 1 3/7
12/5 x 7/10 = 84/50 = 42/25 = 1 17/25
200
This is the improper fraction of the mixed number:
4 9/10
49/10
300
A fraction that is greater than one. The numerator is bigger than the denominator.
Example: 13/2
Improper Fraction
300
When dividing fractions, what do you do to the division sign?
Change it to multiplication.
300
4/7 ÷ 2/3
12/14 = 6/7
300
5 1/2 ÷ 3 2/3
11/2 x 3/11 = 33/22 = 3/2 = 1 1/2
300
This image represents two fractions being divided, using the model method, this number of circles should be drawn.
2
400
A whole number plus a fraction.
Example: 1 1/4
Mixed Number
400
When dividing fractions, what must you do to the second fraction in the problem?
Find its reciprocal or flip it
400
5/9 ÷ 1/2
10/9 = 1 1/9
400
2 5/8 ÷ 1 1/3
21/8 x 3/4 = 63/32 = 1 31/32
400
This image represents two fractions being divided, using the model method, this number of circles should be drawn.
3
500
Also know as the 'inverse'
Found by FLIPPING the numerator and denominator of a fraction. Starts with an 'R'
Example: 1/2 X 2/1 = 1
Reciprocal
500
As a FINAL Answer - Fractions should always be in _______ form.
If possible, convert back to a ____________ number?
Simplest
Mixed
500
3/4 ÷ 7/8
24/28 = 6/7
500
3 1/3 ÷ 2 2/5
10/3 x 5/12 = 50/36 = 25/18 = 1 7/18
500
A student was asked to divide the following fractions, their work is shown below. Are they correct? Explain. If its wrong what is the correct answer?
3/5 ÷ 11/12
5/3 × 12/11
60/33 = 20/11 = 1 9/11
This answer is incorrect, the student flipped both fractions. The correct answer is:
36/55