解:
①15÷4分之5÷7分之8
=15×4/5×7/8
=3×7/2
=21/2
②25-5分之12÷25分之6
=25-12/5×25/6
=25-2×5
=15
③(5分之3+25分之4÷5分之2)×3分之1
=(3/5+4/25×5/2)×1/3
=(3/5+2/5)×1/3
=1/3
⑤17分之12÷3×5分之4
=12/17×1/3×4/5
=4/17×4/5
=16/85
⑥[1-(4分之1+8分之3)]÷4分之1
=(1-5/8)×4
=3/8×4
=3/2
⑦4分之13×4-4÷3分之四
=13/4×4-4×3/4
=13-3
=10
⑧6分之5÷4分之3+6分之1÷4分之3
=5/6×4/3+1/6×4/3
=(5/6+1/6)×4/3
=4/3