Tính bằng cách thuận tiện. a) 250 × 8 × 125 × 40 = .................................... = .................................... = .................................... b) 14+ 1110+ 68+ 910 = .................................... = .................................... = .................................... c) 78× 4 ×14×87 = .................................... = .................................... = .................................... d) 49× 19+ 49× 89 = ............................... ...

a) 250 × 8 × 125 × 40

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b) 14+ 1110+ 68+ 910

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c) 78× 4 ×14×87

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d) 49× 19+ 49× 89

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