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96個. 一共0~4五個數.千位上只能是1、2、3、4四種可能,不可能是0;百位上由於千位上占了一個,加上0,也有四種可能;十比特上由於千位、百位各占一個,剩三種可能;個位由於千、百、十各占一個,剩兩種可能,所以應是4*4*3*2=96.
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