This study examined Korean second and third graders' understanding of multidigit addition and subtraction and particularly their ability to explain the trading required when a column sum of the ...

This study analyzed children's use of mental computation strategies and the standard algorithm on multi-digit subtractions. Fifty-eight Flemish 4th graders of varying mathematical achievement level ...

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.