Friday, November 8, 2013

Multiplication Made Easy (A Computation Strategy)


Can a third grader multiply 74 x 85? If I hadn't seen it with my own eyes, I would say no. But the truth is, kids that have their multiplication facts memorized can multiply two, 2-digit numbers with relative ease.

Here's how.


This is where that place value practice really comes in handy. By breaking the numbers down into their tens and ones and multiplying a series of simpler problems that are then added together to get the answer, what seems nearly impossible is … well … possible.

The computation strategy cards I designed are color coded to help children know where to write each of the numbers and what to multiply and add. Download them free here.

I gave my son an example and he was off and running. I laminated several of the blank cards and added problems at the top in dry-erase marker.


I started with relatively low numbers (e.g. 11 x 20) but after a few of the problems were complete, my son's math ego grew significantly and he was egging me on to make the problems harder.

He checked the answers with a calculator.


To keep track of his success, we used a football scorecard. To make your own, simple print, cut the track out (with a craft knife), along with the football and square. Punch a hole in the latter two, thread a brad through the football, in the track, and attach the square, separating the prongs on the brad to secure it.

As a child answers a problem successfully, the ball is moved from one line to the next.

When my son needed to organize the numbers vertically to add them, he flipped over the laminated scorecard to use as "scratch paper."

After my son practices with these cards more, I'll ask him to draw the steps to a problem himself so he isn't relying on the color coding to find the solution.

4 comments:

  1. Wow.. this is the very easy method to do multiplication. I also enjoyed this method. Thank you.

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  2. Love the strategy cards. Hope you hop over to Math Monday and post it in a few weeks during the Multiplication hop!

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  3. Love it. I have to try it with my second grader who enjoys math.

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  4. Wowza! My kids aren't ready for this, but I'll save it for the day when they're ready to impress their dad :) Love how it shows how to break down numbers. Great number sense activity too!

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