Ο νοερός αριθμητικός υπολογισμός των μαθητών της Γ' τάξης του Δημοτικού σχολείου στις προσθέσεις και αφαιρέσεις διψήφιων αριθμών.

Περίληψη

The purpose of the present study was to investigate what kinds of strategies do students of the third grade of elementary school (8 years old) use when they add and subtract mentally two-digit numbers. 90 students of the third grade (52 boys and 38 girls) participated in the study. The results showed that the children used more flexible strategies in the additions than in subtractions. This implies the particular difficulty of subtractions. Also, the students’ difficulties in subtractions and additions that involve regrouping procedures (“carrying” or “borrowing”) are considerably increased. Finally, the students based mainly on the traditional algorithm – vertical action, a strategy that has been taught in the school. Students’ persistence in this strategy probably influence the emergence of other spontaneous mental strategies.