te explicaré 3 de cada uno:
1)
[tex]1.66666 = \frac{16 - 1}{9} = \frac{15}{9} = \frac{5}{3} [/tex]
[tex]3.126126126 = \frac{3126 - 3}{999} = \frac{3123}{999} = \frac{347}{111} [/tex]
[tex]3.12666666 = \frac{3126 - 312}{900} = \frac{2814}{900} = \frac{938}{300} = \frac{469}{150} [/tex]
2)
[tex]2.75757575 = \frac{275 - 2}{99} = \frac{273}{ 99} = \frac{91}{33} [/tex]
[tex] - 4.12 = - \frac{412}{100} = \frac{103}{25} [/tex]
[tex]0.0121212 = \frac{12}{990} = \frac{2}{165} [/tex]
