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 math standards require that students learn the standard algorithm for multi-digit adding and subtracting—you know, the process in which you line the numbers up vertically to add or ...

The present paper describes the success, the methods (mental, informal written, standard algorithm) and the strategies of informal written arithmetic to be observed when 300 elementary students worked ...