(2/3 + 7/12) = (8/12 + 7/12) = 15/12
16/25 * 15/12 = 4/5 * 3/3 = 4/5
9/10:15/16 = 9/10 * 16/15 = 144/150 = 72/75
4/5 - 72/75 = 60/75 - 72/75 = -12/75
-12/75 = -4/25 = -0.16
564,456,465,645,654...............................
2)6.(24)-5\33=6 24/99-5/33=6 8/33-5/33= 6 3/33= 6 1/11
4)3.(216)+87\111=3 216/999-87/11=3 24/111-87/111=2 135/111-87/111= 2 48/111