69分之67*70
=(69+1)*67/69
=67+67/69
=67又69分之67
8.25÷（7.5/3）÷4
=8.25×3÷7.5÷4
=24.75÷7.5÷4
=3.3÷4
=0.825
7分之5/11分之1+7分之4*11-11
=5/7*11+4/7*11-11
=11*(5/7+4/7-1)
=11*(9/7-1)
=11*2/7
=22/7