Tính bằng cách thuận tiện:

2 × 456 – 2 × 156 + 5 231 = ………………………………… = ………………………………… = …………………………………

2 667 + 590 – 567 + 310 = ………………………………… = ………………………………… = …………………………………22222222

168 413 + 250 930

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183 251 – 169 061

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436 155 × 28

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845 207 : 27

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\(\frac{{39}}{{45}}\) + \(\frac{{13}}{{15}}\) = ………………………………

\(\frac{{21}}{{18}}\) – \(\frac{{10}}{9}\) = ………………………………

9 × \(\frac{5}{{63}}\) = ………………………………

\(\frac{1}{7}\) : \(\frac{5}{{28}}\) = ………………………………