简算：139×137/138+137×1/138 请尽快!

日期：2021-11-14 02:52:09 人气：1

(138+1)×(138-1)/138+(138-1)×1/138
=(138*138-1)/138+(138-1)×1/138
=138-1/138+1-1/138
=139-2/138
=138+136/138
=138+68/69