Răspuns:
Explicație pas cu pas:
a/b xc/d =acxbd
a/b: c/d =a/b xd/c=ad/bc
1 1/4x 2/5= 5/4x2/5=10/20 =1/2
7/8 : b=7/10 b= 7/10 x8/7 = 8/10
ax 1 1/2=5/6 a= 5/6x1 1/2= 5/6x 3/2=5/6x3/2=15x12=5/4
1 1/4:2/5= 5/4 x5/2=25/8
7/8 :b=7/10 b= 7/10 x8/7 =8/10=4/5
a :1 1/2= 5/6 a= 3/2x6/5= 18/10= 9/5
