Go to:
http://seeingmath.concord.org/broken_calculator/
and "break" the 1, 8, 5, 2, 0, 3 and - (minus) keys.
List all the different ways you can make 25 on this calculator with keys that are NOT broken. The first one is done for you.
| 1 |
7 * 3 + 4 = 25 |
| 2 |
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| 3 |
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| 4 |
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| 5 |
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| 6 |
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| 7 |
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| 8 |
How many of these ways will work on the broken calculator? (The first
one is done for you.)
(Only keys that work are: 7, divide, 4, 6, mulitply, open and
close parenthesis, add, equal, and cancel.)
Create more challenges for the students to do!
Learn More
Try some more Broken Calculator challenges at
http://www.fi.uu.nl/toepassingen/00014/toepassing_rekenweb.xml?style=rekenweb&language=en&use=game
and
http://www.mathcats.com/microworlds/broken_calculator.html
Tuesday's lesson - what you can do with a Broken Calculator?
http://www.concord.org/publications/newsletter/2005-fall/tuesday.html
On-math article: Learning Number Sense from a Broken Calculator
Judah Schwartz, George & Judith Collison
https://my.nctm.org/eresources/view_article.asp?article_id=7457&page=1