Đáp án:
a) $\dfrac{41}{33}$
b) $\dfrac{679}{55}$
c) $\dfrac{6367}{300}$
Giải thích các bước giải:
a) $1,(24) = 1 + 0,(24) = 1 + \dfrac{24}{99} =\dfrac{99 + 24}{99} = \dfrac{123}{99}=\dfrac{41}{33}$
b) $12,3(45) = 12 + 0,3 + 0,(45).\dfrac{1}{10} = 12 + \dfrac{3}{10} + \dfrac{45}{99}\cdot\dfrac{1}{10} = \dfrac{12.990 + 3.99 + 45}{990}=\dfrac{12222}{990} =\dfrac{679}{55}$
c) $21,22(33) = 21 + 0,22 + 0,(33).\dfrac{1}{100}=21 + \dfrac{22}{100} +\dfrac{33}{99}\cdot\dfrac{1}{100}=\dfrac{21.9900 + 22.99 + 33}{9900}=\dfrac{210111}{99000}=\dfrac{6367}{300}$
