1. Multiplying and dividing fractions
[N2.3 Support Plenary]
Multiplication and division can be used to check each other.
For example if
120 ÷ 20 = 6 then 120 ÷ 6 should equal 20
and 20  6 or 6  20 should equal 120
In the same way, write down some calculations you could use to check these:
a) 67  13 = 871 b) 14.5 ÷ 0.5 = 29 c) 2.01  0.09 =
d) e) f)
Check the fraction calculations below with the above method.
Don’t forget to jot down your checking calculation before doing it!
g) h) i)
Preamble
These questions recap multiplication and division of fractions through the vehicle of checking multiplications and division. Some pupils may need some initial support either by looking more carefully at (a) to (c) or by considering even simpler calculations like 8 ÷ 2 = 4 or 3  4 = 12. Discussing other checking strategies may be appropriate. To gain more practice pupils could be asked to actually check (a) to (f).
Possible content
Checking divisions and multiplications, dividing and multiplying fractions.
Resources
None.
Solution/Notes
871 ÷ 13 = 67, 871 ÷ 67 = 13 b) 29  0.5 = 14.5, 14.5 ÷ 29 = 0.5
c) ÷ 0.09 = 2.01, ÷ 2.01 = 0/09
d) e) f)
g)  h) i) 
Original Material © Cambridge University Press 2010
Original Material © Cambridge University Press 2010