Last week I had my first private tutoring session with an adorable 3rd-grade boy. You should know that I’m not a real structured tutor–I kinda like to find a starting point and just dive in. My questions and the tutee’s answers guide our path. The starting point for my young friend was how to subtract with regrouping. I gave him the problem 53 – 16 to solve. He looked at it and proudly announced (so fast that I couldn’t even understand without having him repeat it 3 or 4 times…) Bigger Bottom Better Borrow. WHAT?! t became obvious very quickly through questioning that he had NO idea what it meant to regroup and had very little understanding of place value in general.
Let me be clear–it is NOT okay to teach kids tricks or shortcuts such as this. It is a huge disservice to them and to their future teachers.
So I pulled out my trusty base-ten blocks and explained to him about trading tens for ones when we subtract with regrouping. We practiced with the blocks and the algorithm side-by-side. Last week we worked on two-digit minus two-digit, and today I extended it to 3-digit numbers with regrouping across a zero. After just two sessions, he totally gets it. He understands more about place value, and he understands why he does the steps in the standard algorithm. Which brings me to another point. If you have not structured your classroom to be able to work with small groups, you’re not meeting all your kiddos at their level. Whole group instruction addresses the needs of only about 1/3 of your students. There’s no better way to get inside the mathematical mind of a child than to work with them one-on-one or in a small group.
Unfortunately, there are way too many math skills that are taught using tricks. Check out this blog post for an amazing FREE resource to help you Nix the Tricks!