Question

1. Viet cac so sau duoi dang phanso

a, 0,(8)

b, 3,(5)

c, -17,(23)

2. Tinh

A=10,(3)+0,(4)-8,(6)

Answer 1

1)

a) 0,(8) = \(\frac{8}{9}\)

b) 3,(5) = 3 + 0,(5) = 3 + \(\frac{5}{9}\) = \(\frac{27}{9}\) + \(\frac{5}{9}\) = \(\frac{32}{9}\)

c) -17,(23) = -17 + -0,(23) = -17 + \(\frac{-23}{99}\) = \(\frac{-1683}{99}\) +\(\frac{-23}{99}\) = \(\frac{-1706}{99}\)

2) A = 10,(3) + 0,(4) - 8,(6)

= 10+ 0,(3) + 0,(4) - 8 +0,(6)

= 10 +\(\frac{3}{9}\) + \(\frac{4}{9}\) - 8+ \(\frac{6}{9}\)

= \(\frac{90}{9}\) + \(\frac{3}{9}\) + \(\frac{4}{9}\) - \(\frac{72}{9}\) + \(\frac{6}{9}\)

= \(\frac{31}{9}\)