0,(26)=26/99
x=0,(26) 100x=26,(26) 99x=26,(26)-0,(26)=26 x=26/99
13,77777....=13 7/9
x=13,(7) 10x=137,(7) 9x=127,(7)-13,(7)=124 x=124/9=13 7/9
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1)2 38/45-1/15=2 38/45-3/45=2 35/45=2 7/9
2)2 7/9:13 8/9=25/9*9/125=1/5
3)3 3/65*26/99=213/65*26/99=142/165
4)1/5+142/165=33/165+142/165=175/165=35/33=1 2/33
5)18 1/2-13 7/9=18 9/18-13 14/18=17 27/18-13 14/18=4 13/18
6)4 13/18*1/85=85/18*1/85=1/18
7)1 2/33:1/18*1/2=35/33*18*1/2=105/11=9 6/11