17乘21加83乘79？
17x21+83x79=357+6557=6914
17X21+83X79
=17X21+83X21+83X58
=21X(17+83)+83X60-83X2
=21X100+4980-166
=2100+4814
=6914
17ⅹ21+83ⅹ79
=(20-3)(20+1)+(80+3)(80-1)
=400-60+20-3+6400+240-80-3
=(4oo+6400)+(20+240)-(60+80)-6
=6800+260-140-6
=6800+114
=6914
内容全部来源于网络收集，如有侵权，请联系网站删除！
QQ：24596024