,计算下面各题,怎样简便就怎样计算.643-167-133-243 748-351+252-149
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,计算下面各题,怎样简便就怎样计算.643-167-133-243 748-351+252-149
![,计算下面各题,怎样简便就怎样计算.643-167-133-243 748-351+252-149](/uploads/image/z/16510239-63-9.jpg?t=%2C%E8%AE%A1%E7%AE%97%E4%B8%8B%E9%9D%A2%E5%90%84%E9%A2%98%2C%E6%80%8E%E6%A0%B7%E7%AE%80%E4%BE%BF%E5%B0%B1%E6%80%8E%E6%A0%B7%E8%AE%A1%E7%AE%97.643-167-133-243+748-351%2B252-149)
643-167-133-243
=643-243-(167+133)
=400-300
=100
748-351+252-149
=748+252-(351+149)
=1000-500
=500
再问: 1028+54+340+106 38+62-38+62 6300-(3470+1210+790)
再答: 1028+54+340+106 =1028+(54+106+340) =1028+(160+340) =1028+500 =1528 38+62-38+62 =38-38+62+62 =62+62 =124 6300-(3470+1210+790) =6300-(1210+790)-3470 =6300-2000-3470 =4300-3470 =4300-3000-470 =1300-470 =830
再问: 后两个呢?
再答: 没有吗?不是都在吗?
再问: 38+62-38+62
再答: 38+62-38+62 =38-38+62+62 =62+62 =124
=643-243-(167+133)
=400-300
=100
748-351+252-149
=748+252-(351+149)
=1000-500
=500
再问: 1028+54+340+106 38+62-38+62 6300-(3470+1210+790)
再答: 1028+54+340+106 =1028+(54+106+340) =1028+(160+340) =1028+500 =1528 38+62-38+62 =38-38+62+62 =62+62 =124 6300-(3470+1210+790) =6300-(1210+790)-3470 =6300-2000-3470 =4300-3470 =4300-3000-470 =1300-470 =830
再问: 后两个呢?
再答: 没有吗?不是都在吗?
再问: 38+62-38+62
再答: 38+62-38+62 =38-38+62+62 =62+62 =124