Tape Diagrams: 2-Digit Addition and Subtraction | Grade 2. Special | 2m 20s. Your child continues to use tape diagrams as a visual tool to solve word problems. 03/01/2017 | Rating NR.

Ellis showed a subtraction problem, performed both using the traditional regrouping, or borrow-and-carry, algorithm and using an example from the common core. Here’s a screenshot of the two methods.

The Common Core State Standards teach students the algorithm for multi-digit addition and subtraction in 4th grade. But some experts say it should be taught sooner.