Saturday, November 9, 2013

Subtract like a NINJA!

If you follow me on Instagram, you may have noticed that I like math. I REALLY like math... well, second grade math to be exact. Geometry, Trig, Calculus... didn't like that much; however, 2-digit addition & subtraction I LOVE. Math is just so fun to teach and you can apply so many silly stories to any given concept or set of numbers.

subtract like a ninja
Updated Photo: Here are the steps that can be rehearsed with students.

Anyhow, I really wanted to share about how I teach 2-digit subtraction. I shared this photo this past week on IG and realized I needed to share it with more people. I know we all have different practices or methods for teaching these big concepts, but a few years ago I didn't have any. Sad face. After successfully teaching 2-digit addition with regrouping I realized I needed to try a similar approach to subtraction. I had one student who was obsessed with ninjas. So, one night I  had an idea... Subtract like a ninja! I was thinking karate chop, ha-ya, regrouping. I was so excited! I quickly came up with the steps and put it on the Smartboard. We rehearsed the steps with hand motions and they were a hit. This was my first attempt at a ninja and I decided that his head would suffice. I'm pretty sure my first chart had blood dripping from the word regrouping. Perhaps a bit too gory (but well-received by my rough boys).

After spending some time making a model and drawing it, we applied the steps to the algorithm. Hence, the need for 2 karate chops.

If you're looking for a way to teach subtraction, I hope you find this useful . If you have any questions please leave me a comment or email.

UPDATE: Find this 56 page pack in my TpT store! My students placed the pages in their Interactive Math Notebooks.
2-digit subtraction
subtract like a ninja


1 comment:

  1. I am starting subtraction with regrouping this week. My second graders will love this! Thank you for sharing.
    The Traveling Teacher

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