don steward
mathematics teaching 10 ~ 16

Tuesday 15 February 2011


use the digits 1 to 5 once only

form a multiplication sum

in an attempt to find the largest product (result) that can be obtained

an intention is that students try out (on paper) one 4 by 1 digit multiplication and also one 3 by 2 digit multiplication

then they could use a calculator to speed up an exploration of other options - but this might miss out on an understanding of how the 'partial products' contribute

the various (close) options can be considered in an expanded form to see where there are advantages.

the largest is 22, 412 for the first five digits

larger (and smaller) versions of the task can also be explored:

(thanks to Colin Foster for his convenient collection)

and patterns/general formats explored:

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