Odpowiedź:
12.
a) 5/7:3=5/21
6:2 1/5=28/11
7 1/6:9=43/54
b) 2/3:3/5=1 1/9
3 3/7:5/8=192/35
1 3/4:1 3/5=13/32
16.
1 3/4 * 1 1/7 - 3 : 4 1/2 = 7/4 * 8/7 - 3 : 9/2 = 2 - 3 * 2/9 = 2 - 2/3 = 1 1/3
1 5/7 * (2 3/4 - 1 2/3 : 4) = 12/7 * (2 3/4 - 5/3 * 1/4) = 12/7 * (2 3/4 - 5/12) =
= 12/7 * (2 9/12 - 5/120 = 12/7 * 2 4/12 = 12/7 * 2 1/3 = 12/7 * 7/3 = 4
3 1/3 * (2 1/4 - 1 1/2 : 5) = 10/3 * (2 1/4 - 3/2 * 1/5) = 10/3 * (2 1/4 - 3/10) =
= 10/3 * (2 5/20 - 6/20) = 10/3 * (1 25/20 - 6/20) = 10/3 * 1 19/20 =
= 10/3 * 39/20 = 13/2 = 6 1/2
(3 1/4 + 1/2) : [3 1/3 * (1 5/6 - 1 1/12)] = (3 1/4 + 2/4) : [10/3 * (1 10/12 - 1 1/12)] =
= 3 3/4 : (10/3 * 9/12) = 15/4 : (10/3 * 3/4) = 15/4 : 5/2 = 15/4 * 2/5 = 3/2 = 1 1/2
