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How Many Ways Can You Add 34 and 28?

Written by Donna Boucher

Donna has been a teacher, math instructional coach, interventionist, and curriculum coordinator. A frequent speaker at state and national conferences, she shares her love for math with a worldwide audience through her website, Math Coach’s Corner. Donna is also the co-author of Guided Math Workshop.

Back from my mini-Spring Break getaway and eager to get back to work on my newest product, which features adorable monkeys and focuses on addition, subtraction, and place value.  Which brings up the question, how many ways can you add 34 and 28?  Like many of you, I was taught the traditional algorithm for adding multi-digit numbers.  And when I learned it, there was not even any mention of place value–8 + 4 = 12, write down the 2 and carry the 1.  Sadly, there are still teachers today who teach the algorithms for addition and subtraction in a completely rote manner.

So here’s a few different ways you might add these two numbers (adapted from Van de Walle, Teaching Student Centered Mathematics, K-3).

  • Use multiples of 10:  I know that 20 more than 34 is 54 (give kids lots of practice doing this on a 100 chart).  Six more gets me to 60, plus 2 more is 62 (notice that I broke apart the 8 into 6 and 2).
  • Add the tens and then the ones: 20 + 30 = 50 and 4 + 8 = 12 (I would probably think of this as 8 + 2 to make a 10 and then 2 more).  50 + 12 = 62.
  • Move some to make 10s: I can move 2 from the 34 (leaving 32) to the 28 to make 30.  30 + 32 = 62.
  • Use friendly numbers and adjust: 28 is pretty close to 30.  30 and 34 is 64, but I have to take off 2, because 30 is 2 more than 28, so it’s 62.

Challenge your kiddos to show two different ways to add numbers!!

For more on addition, number sense, and place value check out Monkey Business, Adding Tens and Place Value Workstation Activities.

8 Comments

  1. Allison

    We teach these strategies at school (started this year) and the difference in what they can do is AMAZING! I did have to send home a note explaining that this is different than how we (the adults) learned adding.

    Reply
    • Donna Boucher

      Yes! It’s harder for the parents to accept than the students!

      Reply
  2. Ricky M

    I’m a Singapore Math trainer. Loving what I see!!

    Reply
  3. Christine A

    Thank you!! I had one of my teachers asking about this just tonight!!!

    Reply
    • Donna Boucher

      I’ll be that was a great conversation! I just love thinking about computation this way.

      Reply
  4. Diane Tilford

    I’m working with my 2nd graders to make some 10s to add. I have a parent who is very negative and only wants her child to learn the standard algorithm way. I have asked her to remain positive and allow me to show the students that numbers can be added in different ways. She’s very vocal, in front of the class, about this (I’m teaching virtually). Any suggestions on how to help her understand?

    Reply
    • Donna Boucher

      Ask her what her goal is for her child’s mathematics learning. Does she simply want the child to memorize procedures, or does she want the child to have a depth of understanding and be able to work flexibly with numbers? You could quote statistics that indicate that students who learn by memorization do more poorly in international testing than those who learn by exploring multiple strategies. The youcubed website has great information about why we are teaching math in a different way now!

      Reply

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