We write a=3r,b=3s and c=3t where each of r,s,t is between 1 and 8, inclusive. Since a≤b≤c, then r≤s≤t. Next, we note that cab=3t3r3s=3r+s−t, bac=3s3r3t=3r+t−s, and abc=3r3s3t=3s+t−r. Since t≥s, then r+t−s=r+(t−s)≥r>0 and so bac is always an integer. Since t≥r, then s+t−r=s+(t−r)≥s>0 and so abc is always an integer. Since cab=3r+s−t, then cab is an integer exactly when r+s−t≥0 or t≤r+s. This means that we need to count the number of triples (r,s,t) where r≤s≤t, each of r,s,t is an integer between 1 and 8, inclusive, and t≤r+s. Suppose that r=1. Then 1≤s≤t≤8 and t≤s+1. If s=1,t can equal 1 or 2. If s=2,t can equal 2 or 3. This pattern continues so that when s=7,t can equal 7 or 8. When s=8, though, t must equal 8 since t≤8. In this case, there are 2×7+1=15 pairs of values for s and t that work, and so 15 triples (r,s,t). Suppose that r=2. Then 2≤s≤t≤8 and t≤s+2. This means that, when 2≤s≤6,t can equal s,s+1 or s+2. When s=7,t can equal 7 or 8, and when s=8,t must equal 8. In this case, there are 5×3+2+1=18 triples. Suppose that r=3. Then 3≤s≤t≤8 and t≤s+3. This means that, when 3≤s≤5,t can equal s,s+1,s+2, or s+3. When s=6,7,8, there are 3,2,1 values of t, respectively. In this case, there are 3×4+3+2+1=18 triples. Suppose that r=4. Then 4≤s≤t≤8 and t≤s+4. This means that when s=4, there are 5 choices for t. As in previous cases, when s=5,6,7,8, there are 4,3,2,1 choices for t, respectively. In this case, there are 5+4+3+2+1=15 triples. Continuing in this way, when r=5, there are 4+3+2+1=10 triples, when r=6, there are 3+2+1=6 triples, when r=7, there are 2+1=3 triples, and when r=8, there is 1 triple. The total number of triples (r,s,t) is 15+18+18+15+10+6+3+1=86. Since the triples (r,s,t) correspond with the triples (a,b,c), then the number of triples (a,b,c) is N=86.