1. 21,(34)= (2134-21)/99= 2113/99
2. 2,(075)= (2075-2)/999=2073/999
3. 1,23(13)= (12313-123)/9900=12190/9900
4. 0,06(5)= (65-6)/900=59/900
5. 12,3(4)+ 0,5(6)=(1234-123)/90+ (56-5)90= 1111/90+51/90=1162/90
6. 7,(8)-3,4(5)= 78/9-(345-34)/90=780/90-311/90 =469/90
3,8* 0,(5)= 38/10*5/9=38/2*1/9=19/9
3,(63):1,(27)=(363-3)/99:(127-1)/99=360/99*99/126=40/14=20/7
