Question

简便算法①5分之6×15分之2+15分之2÷4分之5 ②10分之9×11-10分之9 ③（13+9分之1）÷9分之13

Answer 1

①5分之6×15分之2+15分之2÷4分之5

=5/6*2/15+2/15*5/4

=1/3*15+1/2*15

=1/15*(1/3+1/2)

=1/15*5/6

=1/18

②10分之9×11-10分之9

=9/10*(11-1)

=9/10*10

=9

③（13+9分之1）÷9分之13

=(13+1/9)*9/13

=9+1/13

=118/13

=9又13分之1