Or search by topic
Most of us can carry out long multiplications using a standard method. But do we understand what we are doing? Here is a chance to find out...
These printable resources may be useful: Methods in Multiplying Madness,
Methods in Multiplying Madness Support.
Will each method always work?
Where is the $20 \times 20$? Where is the $20 \times 3$? ...
Offer students this worksheet with the methods for $23 \times 21$ to make sense of first, as there are no 'carry' digits so it is clearer to see what is going on.
Stu Cork created this GeoGebra file to use with this problem, which he has kindly given us permission to share.