第29页 - 初中数学课课练七年级苏科版

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$ 解：(1)\frac {2023}{2024}=1－\frac {1}{2024}，\frac {2024}{2025}=1－\frac {1}{2025}$

$\frac {1}{2024}＞\frac {1}{2025}，所以1－\frac {1}{2024}＜1－\frac {1}{2025}$

$所以\frac {2023}{2024}＜\frac {2024}{2025}$

$(3)(－\frac {4}{5})－(－\frac {5}{6})$

$=(－\frac {4}{5})+\frac {5}{6}$

$=\frac {25}{30}－\frac {24}{30}$

$=\frac {1}{30}＞0$

$所以－\frac {4}{5}＞－\frac {5}{6}$

$解：小亮：\frac {1}{2}－(－\frac {3}{2})+(－5)－4$

$=\frac {1}{2}+\frac {3}{2}－(5+4)$

$=2－9$

$=－7$

$小丽：(－2)－(－\frac {1}{3})+5－(－\frac {1}{4})$

$=(－2)+\frac {1}{3}+5+\frac {1}{4}$

$=3\frac {7}{12}$

$3\frac {7}{12}＞－7$

$小丽获胜。$