One of the most difficult standards for 1st grade students to own is the idea of adding or subtracting multiples of tens OR a group of ones.  Without it…all other numbers fall apart.

Karen is a phenomenal 1st grade teacher.  Being new to the district, I’m truly thankful for how welcoming her class has been all year long.  Karen’s students get really excited to see me when I walk in the room and that’s such an awesome feeling.  But to be completely honest, I think I get more excited to see them and listen to their thinking.  I guess we’ll say the love is mutual!

I needed to try an idea out, so without warning I showed up to Karen’s class carrying my weapon of choice.


Snap cubes…my weapon of choice.

The activity:

  • Students were asked to get a piece of paper and a pencil.
  • I was going to drop cubes into a basket and students were asked to write down the total number of cubes in the basket.
  • Students had to close their eyes and listen for the cubes dropping.
  • Students were not allowed to used tally marks, numbers, fingers or anything to keep count.  I wanted to see how they were able to image numbers.  We started out by keeping it simple.
  • Being that this was a 1st grade class, all but 3 students were able to get the correct count.
  • I was purposeful to make sure that the iteration between drops wasn’t consistent.  I wanted this to be more than rote counting through rhythm.

Then we moved to counting by tens and ones…

  • I was sure not to just add tens first, then ones.  I wanted to mix it up for an accurate reflection of who could image numbers.
  • This screams formative assessment and small group because of how easy I was able to identify student ability (I like easy).

Then we went for the gusto and did backwards counting by tens and ones…

My Takeaways:

  • The students absolutely loved this activity and so did their teacher.  I am always worried when new things pop in my head and I want to try them out.
  • I was really impressed with how students were able to image numbers.  That is a testament to how Karen has hammered home the idea of tens and ones to her students.
  • There was no way to know if students miscounted because they couldn’t identify the difference in the cubes dropping. Was it a 10?  Or was it a 1?
  • Nowadays I see lots of manipulatives embedded into teaching practice but there still needs to be an opportunity for students to image numbers as they transition through the Concrete-Representation-Abstract model.
  • In the C-R-A model, I seldom see or hear of teachers providing their students an opportunity to employ mental math.  Sure it happens during Number Talks but not beyond that 10 minute-a-day window.  I need to be sure to include the importance of imaging more often.
  • What I liked about this activity was that understanding wasn’t built around skip counting.  It was built around the idea of more and less which focused on quantities.
  • I often forget about an underpinning progression on the road to computational fluency. I’m glad Karen’s class reminded me of the importance in imaging.
    Screen Shot 2015-05-12 at 10.50.30 AM

    The NZ Maths Numeracy Project does a beautiful job focusing on all 3 and how they’re connected.

Stay thirsty my friends!