Thursday, December 31, 2015

Long Multiplication with Google Sheets

My two youngest boys are still in elementary school, so the topic of long multiplication comes up frequently on homework.

Long multiplication is when you multiply two numbers, such as a 3-digit number times a 2-digit number, and you show all the steps by first multiplying by the ones digit, then by the tens digit, then adding together those partial products to get the final answer.

This is a very structured step-by-step method, so it is important for students to be able to follow the process in the correct order. I wondered if Google Sheets could be used to guide a student through the steps, help keep all the numbers organized properly, and provide feedback if the student does something wrong.

The answer is yes!

What I did was create some sheets that allow a student to type in the original multiplication problem, and then using hidden columns, custom formulas, and conditional formatting, it provides the student with feedback each step along the way.

Below are links to access view-only copies of the sheets. You can simply click “File” then “Make a copy” to make your own copies to edit.
Once you have made a copy of the sheet you can:
  • Type in your 2X2 or 3X2 multiplication problem in the gray boxes, one digit per box
  • Multiply by the ones digit and put your results in the yellow boxes
  • Multiply by the tens digit and put your results in the blue boxes
  • Add those numbers and put your results in the green boxes
  • Any wrong answers will be marked in red
  • When done, delete all your numbers to start over with a new problem
Below is a short video showing you an example of using the sheet to work out a long multiplication problem.



Feel free to make copies of these Google Sheets templates to use with students learning long multiplication. I would love to hear any suggestions for improvement or feedback on results.

11 comments:

  1. Wow!! What a neat ideal! I will be sharing this with my teachers, thank you.

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  2. That is awesome!! Thank you for sharing!

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  4. You are incredibly creative Eric! THANKS!! for sharing all your WONDERFUL tools and ideas with the rest of us!! ;-)

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  5. Thanks for sharing. I just shared the link with the teachers in my building!!

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  6. Is there anything like this for Long division?

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    1. I have not made one for long division, but will certainly take a look at that.

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  7. Eric, I think I have one for long division. I am still checking it for errors. But I made one that is 2x1, 3x2 and 3x1. When I think I am done I can send it to you on twitter, if you wouldn't mind checking it out, and of course suggestions would be welcome!

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  8. This is really great because it gives instant feedback to students. Can you make a version that requires a digit instead of a blank space on the second row for the product of the tens digit by the ones digit? We teach it so that a 0 is placed in the ones column instead of leaving the space blank.

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