Best Way to Teach Subtraction with Regrouping | 24 - 8 Posted on November 10, 2014 12:00

The written algorithm of subtraction with regrouping can be pretty confusing to teach and to learn. What does crossing out the number mean? Carrying the one? Etc.

 

When you use Digi-Block, the process of regrouping becomes demystified.The Digi-Block model let’s you visualize and conceptualize the act of regrouping. If you want to take 8 away from 24, you’ll quickly realize there aren’t enough singles (or ones) available to take away 8 ones. So you open up one of the tens You now have one less blocks-of-10, this is the “crossing out” of the 2. When you open that block-of-10 you’re revealing 10 singles. That’s “carrying the one.” In essence, you’re adding 10 ones to whatever amount of ones you started with.

Want to see a different problem modeled out? Let us know in the comments!