2- 3/8÷7/17-1/7
=2-3/8×17/7-1/7
=2-51/56-1/7
=53/56
5/12÷8+18×7/12
=5/12×8+8×7/12+10×7/12
=8+35/6
=13又5/6
3/8÷【(1/2+1/3)×3/30】
=3/8÷(5/6×3/30)
=3/8÷1/12
=3/8×12
=9/2
2- 3/8÷7/17-1/7
=2-3/8×17/7-1/7
=2-51/56-1/7
=53/56
5/12÷8+18×7/12
=5/12×8+8×7/12+10×7/12
=8+35/6
=13又5/6
3/8÷【(1/2+1/3)×3/30】
=3/8÷(5/6×3/30)
=3/8÷1/12
=3/8×12
=9/2