1三年级上册数学三则四则混合运算练习题270=3X92800+32X6(6900-2400)=554=9X860X8+157022X4+22140=2+1749X4+420120X5=230=5+24066X5+77480X6X2807+20=235-35=7600-12X3640+60X442=7+36=610X4-20=4630=9+320300=6X9(72=9)+(56=8)280X4=560=(23-17)21X3+410147+72=82X80=4202+36=981=9+877921+7X4770=7+65100-50=5302+30X264=8+4565X7-48=637X4+19X815=3+10=5225=5+42=672=9-36=672=8+9X525=5-16=4500X(400-396)564+264-45365X9-4509000-(4500+250)14X6+9X5180=9-42=68X(910-720)6500+1250-350035=5+8X721X4-54=936=4+21X256=7+36=672=9-57650-(546+4530)9X80+9806700+72=8900=(72-68)12=6+45X3760-540+111080X30+56009450-3200-4200800X7-180824=4X3201+232-365(159-87)=32400=6-451600=2+230(601-246)=5(25+38)X151500-125X825X8X9201+232-3652+3X56735-35X12789-13X4521X3+410147+72=82X80=420+36=981=9+877921+7X4770=7+65100-50=5302+30=240+100=560-12X3640+60X4500X(400-396)