1. 35% x 7分之4 x 20分之93 - 40%
=7/20x4/7x93/20-0.4
=1/5x93/20-0.4
=0.93-0.4
=0.53
2. 13分之5 x 25% + 13分之8 x 4分之1
=5/13x1/4+8/13x1/4
=(5/13+8/13)x1/4
=1x1/4
=1/4
3. （4分之3 - 3分之1 x 25%) 除以 0.25
=(1/4x3-1/3x1/4)x4
=3-1/3
=2又2/3