巧算【789+789789+789789789】/【987+987987+987987987】1-2/3-2/9-2/27-2/81-2/243

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/29 06:58:30
巧算【789+789789+789789789】/【987+987987+987987987】1-2/3-2/9-2/27-2/81-2/243

巧算【789+789789+789789789】/【987+987987+987987987】1-2/3-2/9-2/27-2/81-2/243
巧算【789+789789+789789789】/【987+987987+987987987】
1-2/3-2/9-2/27-2/81-2/243

巧算【789+789789+789789789】/【987+987987+987987987】1-2/3-2/9-2/27-2/81-2/243
【789+789789+789789789】/【987+987987+987987987】
=789*(1+1001+1001001)/[987*(1+1001+1001001)]
=789/987
=263/329
1-2/3-2/9-2/27-2/81-2/243
=1-(1-1/3)-(1/3-1/9)-(1/9-1/27)-(1/27-1/81)-(1/81-1/243)
=1-1+1/3-1/3+1/9-1/9+1/27-1/27+1/81+1/81-1/243
=1-1/243
=242/243