3) a)(3/4 + 1/2) : 15/8 = (3/4 + 2/4) : 15/8 = 5/4 x 8/15 = 2/3
b)(2/5 - 0,1) : 0,6 = (4/10 - 1/10) : 6/10 = 3/10 x 10/6 = 1/2
c) 6/7 : 2/3 + 5/7 = 6/7 x 3/2 + 5/7 = 18/14 + 5/7 = 9/7 + 5/7 = 14/7 = 2
d)9 + 0,(3) : 1/3 = 9 + 3/9 : 1/3 = 9 + 3/9 x 3/1 = 9 + 1/3 x 3/1 = 9 + 3 = 12
e)2/3 - 1/2 : 3 = 2/3 - 1/2 x 1/3 = 2/3 - 1/6 = 4/6 - 1/6 = 3/6 = 1/2
f)0,75 : (2/3 - 0,5) = 75/100 : (2/3 - 5/10) = 75/100 : (20/30 - 15/30) = 75/100 : 5/30 = 75/100 x 30/5 = 15/100 x 30/1 = 15/10 x 3/1 = 45/10
4) a)(5/6)² : 10/9 = 25/36 x 9/10 = 25/4 x 1/10 = 25/40
b)(9/5)² : (6/10)² = 81/25 x 100/36 = 81/1 x 4/36 = 324/36
c)1/4 + 1/9 : (2/3)² = 1/4 + 1/9 : 4/9 = 1/4 + 1/9 x 9/4 = 1/4 + 1/4 = 2/4
d)0,(1) : 0,(3)² = 1/9 : (3/9)² = 1/9 : (1/3)² = 1/9 : 1/9 = 1/9 x 9/1 = 9
e)2/3 - 1/3 : 1/2 = 2/3 - 1/3 x 2/1 = 2/3 - 2/3 = 0
f)(5/6 - 2/3)² : (6/9)² = (5/6 - 4/6)² : (2/3)² = (1/6)² : 4/9 = 1/36 x 9/4 = 1/4 x 1/4 = 1/16
