Monday, February 09, 2015

Math Monday -- Math Ditties and Tricks

I saw this graphic on Lester Laminack's FB page and started thinking about the ditties and tricks we teach. When are they a good support, and when does a learner spend so much time on the trick that they might as well just learn the fact or concept?

The one above is catchy and fun, but we don't teach all of those concepts in the same grade. So, by the time a student is learning to find the mean, and therefore might be ready for the rhyme, one would hope that they had already internalized median, range, and mode.

You know that trick for the nines table in multiplication that you can do with your hands? ("Holding both hands in front of you, number the digits from left to right so the left pinkie is 1. Then bend down the finger you want to multiply by -- so if you're multiplying 9x4, bend down the fourth finger. The fingers to the left of the turned-down finger are the "tens" digit of the answer (3), and the fingers to the right are the "ones" digit of the answer (6)." description found here) Kids love knowing that trick, but if you have to put your pencil down and hold both hands in front of you to solve a multiplication problem, you might as well just learn the facts.

What are your favorite tricks or ditties to teach as you help your students internalize the fact or process?

What tricks or ditties drive you crazy because they have become more important than the underlying fact or concept?

It's Math Monday! Join Mandy at Enjoy and Embrace Learning for the Math Monday link up!


  1. Great post to cause thinking. I have honestly never understand the finger thing because I learned for multiplying 9s - 9 x 6 would be...take one away from the number other than the 9, so you have 5 and 5 plus ? = 9, 4 put 5 and 4 together is 54. I'm pretty sure this shows no understanding but I can do it faster than using the finger trick you shared. :) Thanks for joining this week.

  2. I still find PEMDAS useful (or, please excuse my dear Aunt Sally), and I recall learning a "rap" in 4th grade about how to do long division: You divide, multiply, subtract, and bring down (repeat ad nauseum). I believe we had to perform it for other classes, which definitely made for a substantial investment of class time ...

  3. Also, totally not math related, but every year I let my kids watch the video and attempt to sing along to the Preposition Song (to the tune of Yankee Doodle). Hilarious, but certainly not worth actually attempting to memorize.

  4. Anonymous4:33 AM

    Great post! I have never thought of the nines multiplication trick being bad because I used it. But, when you look at it the way you explained it, it does make sense to actually learn it rather than constantly waste time by trying to stop everything to hold your hands up and look at them. The trick I really like is the saying for the metric system (King Henry died from drinking chocolate milk). I think this is really useful because since we don't use the metric system it is harder for young kids to learn and really understand and know the conversions of it.

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  6. This is just the BEST in terms of poetic form, and it's adorable - but you're right - it mushes together a lot of concepts that aren't taught all once. I think it's meant to be accessible for adults who allegedly have already learned.

    My husband learned the hand nine thing; I spent my summers memorizing the tables to 13, so I could NOT understand it, and never taught it when I was teaching - I doubt memorization serves everyone well, but better, maybe, to allow the learner to find their own shortcuts rather than teaching ones which may not make sense.

  7. This is not a ditty, but hopefully a slam dunk for understanding facts. My first graders have been working to answer this question- How is addition related to subtraction?" During this investigation one student added, " If 5+5=10 and 5x5 =10 then how is multiplication like addition?" If these curious mathematicians can discover the connection now, they will be a slam dunk by third grade!


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