Note that all integer x work. If x is not an integer then suppose n<x<n+1. Then x=n+2n+1k, where n is an integer and 1≤k≤2n is also an integer, since the denominator of the fraction on the right hand side is 2n+1. We now show that all x of this form work. Note that x2=n2+2n+12nk+(2n+1k)2=n2+k−2n+1k+(2n+1k)2. For 2n+1k between 0 and 1, −2n+1k+(2n+1k)2 is between −41 and 0, so we have n2+k−1<x2≤n2+k, and ⌈x2⌉=n2+k. Then, ⌈x⌉+⌊x⌋⌈x2⌉+⌈x⌉⋅⌊x⌋=2n+1n2+k+n⋅(n+1)=n+2n+1k=x so all x of this form work. Now, note that the 2n solutions in the interval (n,n+1), together with the solution n+1, form an arithmetic progression with 2n+1 terms and average value n+2n+1n+1. Thus, the sum of the solutions in the interval (n,n+1] is 2n2+2n+1=n2+(n+1)2. Summing this for n from 0 to 4, we get that the answer is 02+2(12+22+32+42)+52=85.