Răspuns:
32x40=32x(4x10)=(32x4)x10=128x10=1280
48x30=48x(3x10)=(43x3)x10=129x10=1290
51x30=51x(3x10)=(51x3)x10=153x10=1530
65x60=65x(6x10)=(65x6)x10=390x10=3900
63x50=63x(5x10)=(63x5)x10=315x10=3150
61x90=61x(9x10)=(61x9)x10=549x10=5490
3x20=3x(2x10)=(3x2)x10=6x10=60
58x30=58x(3x10)=(58x3)x10=174x10=1740