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 ...

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.

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 ...

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. Now, he solves for an unknown in any ...