BOX OUT!
INTRODUCTION
I swear the internet is really creepy sometimes! We had been talking about subtraction and my mom had just sent me a lesson with subtracting with zeros- and then the next morning I wake up and the first image I see on Pinterest is a cool chart that applies to all of subtraction!
I really loved this chart, because it really covers all of the basics of subtraction! I thought this would be a great chart to display in the classroom for students to remember. I know as a kid, it was always easier for me to remember things when they were either in a pneumonic device or rhymed. I thought this was too good not to share!
3 DIGIT SUBTRACTION WITH ZEROS
Going off this great chart, I thought I would continue with another trick that my mom was saying she uses with her students, which is this concept of "boxing out." In this concept, students must ask themselves 2 questions: 1) Is there a middle zero? 2) Does the ones column need help? If the answer is YES to both, then the student must put a box around the tens and hundreds place (see below) This will help them see where they are getting the "extra 1" that will be carried over to the ones column. If the answer is not YES to both questions, then students can use the basic subtraction rules that are listed above. There is no need to box out two numbers, this only applies if the answer to both questions are YES.
Below is a sample worksheet to help students work with boxing out!
REFLECTION
I really love using charts to help students remember concepts. I always found little tricks and analogies always helped me remember how to do things in math as a kid. In fact, almost all of what I remember today about my elementary school math are things like what is shown above, where it was easy to remember. Other examples of this include: PEMDAS, Keep.Change.Flip, The Butterfly Method, etc. I thought both the chart and the lesson about boxing out make a lot of sense and are easy to remember for kids. Another thing I seem to be learning from seeing all of these various worksheets from teachers is to put reminders of the little tips or tricks on the worksheet and it's also really helpful to get the first problem started to help students.
Hi Mackenzie! Thank you for sharing your tips. I really like this. I think with all that kids learn, the charts and the questions can really help, especially in a time when the student is having trouble remembering what to do.
ReplyDeleteThe box it out tip is really neat. It helps students to see both numbers get changed but keeps it a more simple perspective to box out the 70 above, change it to one less. I have seen a visual method like this really help students who have a visual difficulty in seeing columns in line, or have difficulty remembering multiple steps to solve a math problem.
Nice post and good job. I'm glad I found your blog. I had looked for your posts before and had gone to the blog with one d in the maddness part of the address (which didn't show any posts).