don steward
mathematics teaching 10 ~ 16

Tuesday, 20 May 2014

fraction multiplication pictures

using diagrams to show a fraction multiplication result seems helpful
because it fits with other uses of an 'area' model for multiplication
and seems effective in terms of conveying some rationale for the process

however, there are a few weeny complications with it

what do these fraction multiplication pictures show?

technically, a fraction of a length multiplied by a fraction of a different length is a fraction of the area of a rectangle, so for the first picture:

to a certain extent the complication is simplified by having fractions of unit lengths (in a unit square, making L = 1 and W = 1 and so LW = 1)

this is an approach taken by the helpful:
learning objects
fractions of fractions tool

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