﹙2分之1＋3分之1﹚÷5分之2－4分之3
=（1/2+1/3）÷2/5-3/4
=（3/6+2/6）x5/2-3/4
=5/6x5/2-3/4
=25/12-9/12
=16/12
=4/3
0.1×99 99×99 99分之98
=9999x98/9999x0.1
=98x0.1
=9.8