Base 10 blocks examples9/11/2023 This lets them easily see the two different numbers they are composing. I’ve found that using base-ten blocks and having to “trade-in” can be a huge hurdle for many second graders, and unifix cubes eliminate it (especially when it comes to subtraction with regrouping!).įinally, I much prefer students be able to individually build each of their two-digit numbers with unifix cubes in different colors (keeping them in sticks of ten with extra units). Unlike using base-ten blocks, the act of regrouping when using unifix cubes doesn’t have to include “trading in.” Instead, the focus can be on the visual of regrouping the unifix cubes. This helps build the foundational understanding of building numbers with units of tens and ones. The result is that they are far less likely to name the value of a ten stick as “one” instead of “ten”. When creating sticks of ten with unifix cubes, students can physically separate the ten stick. It is by far the NUMBER ONE math manipulative I use in first and second grade for so many reasons, but especially because it avoids all of the issues mentioned above. There is no point in sharing problems without offering a solution, right? Well, here’s my solution: Unifix Cubes! They won’t be able to have that concept of ten and regrouping reinforced because base-ten blocks do not make that scaffolding possible. They won’t be able to see the ones that were regrouped to make a new ten. However, one thing they will not be able to see once composed are the individual addends that created that sum. They may even be able to regroup those ones and create a new ten with two extra ones. They may be able to put the twelve ones together. They may be able to put the three tens together. This can be especially important when regrouping!įor example, if I am asking students to show 25+17, they may be able to represent 25 and 17 separately with base-ten blocks. When using base-ten blocks, you can begin by separating the two addends into different piles, but once composed, there is no distinguishing between the two addends. When teaching addition, whether it’s adding single-digit numbers with sums beyond ten, or you’re introducing double-digit addition, it really helps to see the individual addends. (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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