六年级毕业简便计算拓展训练用简便方法计算下列各题:199719961996-199619971997(乘法分配律)100+99+98+97+4+3+2+1(等差数列求和)4.5 + 6.5 -0.125(乘法分配律)+ + + + + + (分数的拆分)(数形结合)1(23)(34)(45)(56) 999111+33366799(1 )(1 )(1 )(1 ) 2003(1+ + + )(+ + +)(1+ + + +)(+ + )9+99+999+9999+99999+5999111+333667(2.87.24)(3.61.40.5)(4.853.6+6.153)140 200620082008-200820062006(2+)+(2+2)+(2+3)+(2+11)12 -22+32-42+52-62+-1002+1012