【题目】用简便方法计算
138+237+63 124+298+276+202
262+(189+138) 347+118+282
【答案】438；900
589；747
【解析】
138+237+63
=138+(237+63)
=138+300
=438
124+298+276+202
=124+276+298+202
=(124+276)+(298+202)
=400+500
=900
262+(189+138)
=262+189+138
=262+138+189
=400+189
=589
347+118+282
=347+(118+282)
=347+400
=747
