1. Written methods Here are some calculations and their answers.
[N4.1 Core Plenary]
Here are some calculations and their answers.
All the calculations are wrong.
Explain what common error the person has made in each case and work out the correct answer.
(1)
(2)
(3)
(5)
(4)
(6)
Preamble
This activity, for individuals or small groups, gives children the opportunity to look closely at some answers in order to identify the more common errors made. Hopefully during the course of this exercise children will become more aware of the correct methods by directly confronting common errors.
Possible content
Practicing non-calculator calculations by looking for errors.
Resources
None.
Solution/Notes
(1) 230, it’s the number that moves not the decimal point.
-0.875, numbers incorrectly lined up
(3) 701, ignoring the zero division
640, ignoring division by decimal
(5) 0.05, dividing largest by smallest
(6) , ignoring the zero tenths in 5.04
(7) , careless over zero tenths
(8) 0.25, dividing largest by smallest in error.
(7)
(8)
Original Material © Cambridge University Press 2010
Original Material © Cambridge University Press 2010