=[382+498×(382- 1)]/(382×498- 1 1 6)
=(382+498×382-498× 1)/(382×498- 1 16)
=(498×382+382-498)/(382×498- 1 16)
=(498×382- 1 16)/(382×498- 1 16)
= 1
5 1/2/3×3/5+7 1/3/4×4/7+9 1/4/5×5/9
=50/3/5×3/5+70/7/4×4/7+90/5/9×5/9
=3 1+4 1+5 1 = 123