A multiplication algorithm for whole numbers, using the area model for multiplication

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Change the factors with the sliders:
H, T, and O are the hundreds, tens, and ones digits for the first (horizontal) factor; h, t, and o are for the second (vertical) factor.

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In the U.S., paper-and-pencil multiplication is taught with a method that starts with ones times ones. This diagram shows that ones times ones is a tiny part of the product. Could you invent a multiplication method that starts with the highest place values?

Can you adapt this diagram/method to multiply decimals? Maybe think of the numbers on the axes as counting hundredths instead of ones (for example, 37 might mean 37 hundredths, or 0.37.)

Susan Addington, Created with GeoGebra

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Last updated December 20, 2009

Copyright 2009-10 David Dennis and Susan Addington. All rights reserved.