Ta đặt:
$A=\dfrac{6}{5.8}+\dfrac{22}{8.19}+\dfrac{24}{19.31}+\dfrac{140}{31.101}+\dfrac{198}{101.200}$
$⇔A=\dfrac{2.3}{5.8}+\dfrac{2.11}{8.19}+\dfrac{2.12}{19.31}+\dfrac{2.70}{31.101}+\dfrac{2.99}{101.200}$
$⇔A=2[\dfrac{3}{5.8}+\dfrac{11}{8.19}+\dfrac{12}{19.31}+\dfrac{70}{31.101}+\dfrac{99}{101.200}]$
$⇔2A=\dfrac{1}{5}- \dfrac{1}{8}+ \dfrac{1}{5}- \dfrac{1}{19} +\dfrac{1}{19}-\dfrac{1}{31}+ \dfrac{1}{31}-\dfrac{1}{101}+\dfrac{1}{101}-\dfrac{1}{200}$
$⇔2A=\dfrac{1}{5}- \dfrac{1}{200}$
$⇔2A=\dfrac{39}{200}$
$⇔A=\dfrac{39}{100}$
