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.

So it shouldn’t come as a surprise that the standard algorithm is really just an application of the distributive property. Let’s see why. Think about multiplying two arbitrary two-digit numbers ‘ AB ’ ...