脱式计算2800 100789 (947599)64 36(27623)(9325)9 723(521504) (3921)396391363 3841231 (3713) 3016 (17-8) 28(9632) (72-54)9571235 84864016 15003245(5438)6 (24+80)50 32(25+125)1233+85 25(24+16) 17899+178(140-70)54 84242 4907+2445+24012 157+857 (46-20)30-9025274 (404)25 2400801428336060) (42048)(375345) 2900(34+99)142549 75425 167676720362 9953+53 450(169)245(45+39) 125(84)5 4125-25420(205198)4 460(29183) (960400)70(140-70)54 63+84242 4907+245(404)25 240080142 108(8336060)(42048)(375345) 290(343+99) 142549+14 1676766 9953+53 4502(169)245(45+39) 125(84)5 4125-25口算