253×56=14168,
253
× 56 1518
,1265 14168
503×32=16096,
503
× 32 1006
,1509 16096
45×240=10800,
45
×240 180
,90 10800
※336÷21=16,
16
21
336
21 126
,126 0
验算:21
×16 126
,21 336
※858÷39=22,
22
39
858
78 78
,78 0
验算:39
×22 78
.78 858