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.

Joke Torbeyns, Lieven Verschaffel, Mental computation or standard algorithm? Children's strategy choices on multi-digit subtractions, European Journal of Psychology of Education, Vol. 31, No. 2 (April ...