(Yes, I promise I will share what I do below!) Cannot See Individual Addends When building a foundational understanding, I prefer to eliminate those obstacles. You might ask, well isn’t that what “trading in” is? YES! However, “trading in” expects the student to be able to keep track of their tens and ones while trading, which for many students is too many steps to navigate. It is an extra step that can get in the way of building the foundational understanding of making a new ten. I’ve found that using base-ten blocks and having to “trade-in” can be a huge hurdle for many first and second graders. I personally do not like introducing the ideas of regrouping using base-ten blocks (whether we’re working with double-digit addition with regrouping, or more foundational addition strategies like “making ten to add”). (Don’t worry! I’ll tell you WHAT I use shortly!) Regrouping (Trading In)
If the manipulative itself causes confusion, it makes more sense to use a different manipulative to begin the foundational understanding of addition and subtraction beyond ten. While this is true, I believe that manipulatives are meant to support new understanding. One could argue that the one way students will learn that a ten rod represents “10” is through exposure to those manipulatives. This can pose a big problem when you’re trying to introduce a new concept like adding numbers beyond ten. That means that when they’re counting 2 ten sticks and 3 ones, they count “5” instead of “23”. They often see it as a single unit (which makes sense since the pieces are affixed to each other). One problem that I run into (especially in first grade) is that many students do not see the ten rod as a unit of ten. 3 Issues with Base-Ten Blocks Counting “Ten” as “One” So here we are: Why I don’t use base-ten blocks to teach addition and subtraction, and what I use instead. This answer surprised A LOT of teachers, and several asked for a deeper explanation… The truth is that while I use base ten blocks to help represent numbers with my students and practice concepts of hundreds, tens, and ones, I DO NOT use them in first and second grade to teach addition and subtraction. One of the biggest questions I received was why base-ten blocks didn’t show up on my first and second-grade lists, and only made an appearance when we got to third grade. I recently shared my top five math manipulatives for first, second, and third grade.
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