Tính rồi thử lại (theo mẫu)

Mẫu: \(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{5746}\\{1962}\end{array}} \\\,\,\,3784\end{array}\) Thử lại: \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{3784}\\{1962}\end{array}} \\\,\,\,\,5746\end{array}\)

a) 8 923 – 4 157

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27 069 – 9 537

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b) \(\frac{8}{{15}} - \frac{2}{{15}}\)

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\(1 - \frac{3}{7}\)

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c) 7,284 – 5,596

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0,863 – 0,298

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Cho phép tính a + b = c. Chọn phát biểu sai?