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可以這樣算比如53×89=那看成是53×90-53=4770-53=4717,簡單一點吧或是67×91=67×90+67=6097這個還是要靠一點運算能力的還有一種口算灋:比如38×94可看成3×9×100+(3×4+8×9)×10+4×8=2700+840+32=3572怎麼…
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