А 3/7*(1/3+4/9)= б 4/5-1/4:5/6=

Question

А 3/7*(1/3+4/9)= б 4/5-1/4:5/6=

Answer 1

А)
3/7 *  (1/3+4/9) =  1/3
1) 1/3+4/9 = 3/9+4/9= 7/9
2) 3/7  *  7/9 =  (3*7)/(7*9) = (1*1)/(1*3)=1/3

б)
4/5 -  1/4 :  5/6 =1/2
1) 1/4  :  5/6  =  1/4   *  6/5  = (1*6)/ (4*5) = (1*3)/ (2*5) =3/10
2) 4/5  -  3/10=  8/10-3/10= 5/10 =  1/2