TY  - JOUR
AU  - Milosav M. Marjanović
AU  - Aleksandra N. Mandić
TI  - Understanding algorithms of vertical addition and subtraction
JO  - The Teaching of Mathematics
PY  - 2009
SP  - 57 
VL  - XII
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/TM2_2009_XII_2_a1/
LA  - en
ID  - TM2_2009_XII_2_a1
ER  -