Keith Burnett, Sutton Coldfield College, [email protected] Adding and Subtracting Quick and Dirty Fractions Method! Adult Numeracy N2/L2.4: Use

Keith Burnett, Sutton Coldfield College, [email protected]

Adding and SubtractingQuick and Dirty

Fractions Method!Adult Numeracy N2/L2.4: Use fractions to add, subtract, multiply and divide amounts or quantitiesFunctional Mathematics Level 2: Add and subtract fractions- add and subtract using halves, thirds, quarters, fifths and tenths

Kindly contributed to www.skillsworkshop.org by Keith Burnett, Sutton Coldfield College. [email protected] To see more of Keith’s resources, including a traditional approach to adding and subtracting fractions visithttp://www.slideshare.net/keithpeter

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You can add two fractions by doing three multiplications and an addition!


3

52

3


3

52

3


3

52

3


3

52

3


3

52

3


3

52

3

3 3


3

52

3

9


3

52

3

9


3

52

3

9 5 2


3

52

3

9 10


3

52

3

9 10


3

52

3

9 10

5 3


3

52

3

9 10

15


3

52

3

9 10

15

+


3

52

319

15

9 10

15

+


3

52

314

15


An example that has denominators with a common factor…


5

64

9


5

64

9


5

64

9

5 9


5

64

9

45


5

64

9

45


5

64

9

45 24


5

64

9

45 24


5

64

9

45 24

54


5

64

9

45 24

54

+


5

64

969

54

45 24

54

+


5

64

969

54


5

64

9115

54


5

64

9115

54

5


5

64

9115

54

5

18


5

64

915

18


You had to cancel down at the end because of the common factor…


Mixed numbers?


Mixed numbers?Just convert to improper fractions and carry on…


Subtraction?


Subtraction?Just subtract the top totals instead of adding…


Your turn…


4

57

2Answer on next slide…


4

57

24

3

10


Make up some more questions and check them with your calculator

Documents

Keith Burnett, Sutton Coldfield College, [email protected] Adding and Subtracting Quick and Dirty Fractions Method! Adult Numeracy N2/L2.4: Use