Subtraction’s a Drag

I’m never ceased to be amazed by the terrific resources and websites that hide from me on our school district’s very own shared drives. I’m sure it’s the same for many other educators out there; while you’re busy searching the Internet for a particular websites, resource, or learning tool, you miss some of the terrific findings and resources that may already be in use in the classroom next door. Such was the case this morning, when I walked into one of the computer labs here at school and saw the Thursday Morning Math Club working hard at their subtraction skills, particularly with borrowing and carrying.

The tool they were using to complete their subtraction problems was found at the ever popular Mr. Nussbaum.com website, which I’ve mentioned before, and will have to keep an eye on. The Draggable Fractions tool allows you to complete complex subtraction problems via the borrow and carry system without having to smudge up a paper with all of the necessary pencil and eraser marks as you carefully try to cross out, erase, carry over, and otherwise make a mess out of a problem on paper. Instead, simply drag the numbers you need from the number bank, and drop them into place above each column. For me, just thinking about trying to cram all those tiny numbers into such a small space on my paper makes me cringe (is that a 12 I created after carrying over, or a 1 from the previous column and a 2 in this one?). When you first load up the site, you are asked how many problems you’d like to solve in total, how many digits you want the first number to have, and how many digits you’d like the second number to have. It’s your own personal customizable practice sheet of problems, and you don’t have to worry about making any photocopies from the workbook.

As I watched the students putting slashes through numbers and literally dragging the little numbers from the number bank and dropping them onto the problem, the entire process of “borrow and carry” started to make much more sense as a “drag and drop” process with the mouse. The students were highly engaged (these were third and fourth graders, so older students might need not be as excited), and many wanted to know if I could let them do it during computer lab time later that day. While I told them that it would make a much better activity for their own classroom’s computer (as an extra tool during math time or to help struggling students with some extra practice), I couldn’t help but wonder how many other teachers in the building didn’t know about the resource either. I guess I have some work to do this Spring Break as I dive into what other treasures the network drives are hiding.