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.

Consider the standard algorithm for multidigit addition and subtraction, which makes its appearance in Grade 4 of the Common Core math standards.

This new technique is part of the controversial Common Core Standards, which also introduced a new way of doing subtraction. NPR recently demonstrated the "box method" by having a fourth grader ...