Algebra CAT Puzzle - Solution
The Puzzle:

CAT = (C + A + T) × C × A × T
Our Solution:
135 = (1 + 3 + 5) × 1 × 3 × 5
If you allow A=T, then another solution (supplied by Bill Elliott) is:
144 = (1 + 4 + 4) × 1 × 4 × 4
If you allow A=T, then another solution (supplied by Bill Elliott) is:
144 = (1 + 4 + 4) × 1 × 4 × 4