Coba jelasin Contoh: dari Pengurangan dong

"1234 − 567 =" dapat diselesaikan sebagai berikut:

Subtraction in the United States: An Historical Perspective, Susan Ross, Mary Pratt-Cotter, The Mathematics Educator, Vol. 8, No. 1 (original publication) and Vol. 10, No. 1 (reprint.) PDF