.
用竖式计算并演算. 139+682= 701﹣573= 452﹣189=
(1)从熊猫馆到飞禽馆最远要走多少米?(2)老虎馆到熊猫馆比老虎馆到飞禽馆近多少米?
684+235=验算: 902﹣637=验算: 527+343=验算: 485+87=验算:
口算.20+50= 7034+43= 7778﹣54= 2410+20+50= 99﹣78= 2172+16= 8890﹣40= 5090﹣50+30= 6+43= 4945+50= 9548﹣5= 4380﹣20﹣30= 67﹣13= 5423+45= 6895﹣54= 4160+30﹣50= .