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.

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.

In the CCSS, it’s actually referred to as the “standard algorithm” for addition and subtraction, and the CCSS require that students completely master it for multi-digit numbers by the end of ...