1.依据题意设该整数为K,则有如下等式K=M/(M+1)+N/(N+1)+P/(P+1)+Q/(Q+1).(1)
因为:M/(M+1)=1-1/(M+1)
N/(N+1)=1-1/(N+1)
P/(P+1)=1-1/(P+1)
Q/(Q+1)=1-1/(Q+1)
所以:K=M/(M+1)+N/(N+1)+P/(P+1)+Q/(Q+1)=1-1/(M+1)+1-1/(N+1)+1-1/(P+1)+1-1/(Q+1)
=4-[1/(M+1)+1/(N+1)+1/(P+1)+1/(Q+1)]
所以:2