adding and subtracting quick and dirty fractions method!

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!


35

23


35

23

3 3


35

23

9


35

23

9 5 2


35

23

9 10


35

23

9 10

5 3


35

23

9 10

15


35

23

9 10

15

+


35

23

1915

9 10

15

+


35

23

1 415


An example that has denominators with a common factor…


56

49


56

49

5 9


56

49

45


56

49

45 24


56

49

45 24

54


56

49

45 24

54

+


56

49

6954

45 24

54

+


56

49

6954


56

49

11554


56

49

11554

5


56

49

11554

5

18


56

49

1 518


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…


45

72

Answer on next slide…


45

72

4 310


Make up some more questions and check them with your calculator

adding and subtracting quick and dirty fractions method!

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