I’ve said it before and I’ll say it again…rekenreks are one of the best tools for building number sense out there and our kiddos are IN LOVE with them!
I introduced the math racks to my students 2 weeks ago and they have not lost their luster!
We started with simply exploring the new tools and talking about what we noticed. It didn’t take long for them to see that there are 10 beads on top and 10 on bottom. They also quickly saw that there were 5 red and 5 white on each row.
I revisited the term “subitize” with them and reiterated that it means to see a number without counting. I told them that when we use a math rack, we have a starting position. On our particular math racks, we use red in the middle and start with the beads on the right. We slide them to the left to read them since we read from left to right. We practiced sliding the beads. I then told them that their challenge was to never use more than one pull per row. If they needed to count their beads in the beginning, they must count them first and then slide them altogether. Our goal was to get quicker each time at seeing the numbers without counting. They stepped up to that challenge immediately!
I like to use the Dreambox Teacher Tool to have students practice subitizing. They watch the quick image of the math rack and then they make it on their board. We then talk about what they saw. It didn’t take long for them to start saying things like, “I knew it was 6 because all the red beads and 1 more white bead were showing” or “I knew it was 9 because only one bead was missing.”
We have since been using them to make ten and next week one of my groups will start the teen numbers and another will use them to solve addition problems like 8 + 5 by first making a ten. I love to demonstrate this in conjunction with place value arrows, so stay tuned for some pics and a lesson!
Rekenreks not only build number sense, but they provide a means for rich mathematical conversation, noticing and wondering!