1.65×（5-2又6/7）÷1.25 / （3/7+1又1/3）÷7/9×1.1
=33/20x(5-20/7)÷5/4 / （3/7+4/3）x9/7x1.1
=33/20x15/4x4/5 / (9/21+28/21)x9/7x11/10
=99/20 / 99/70 x37/21
=70/20x37/21
=7/2x37/21
=37/6