The NOT operation changes all the 0s to 1s and all 1s to 0s; e.g., NOT(00110) is 11001 and NOT(10100) is 01011.
+----+----+----+----+----+ | 1 | 2 | 3 | 4 | 5 | +----+----+----+----+----+ | 2 | | | | | +----+----+----+----+----+ | 3 | | | | | +----+----+----+----+----+ | 4 | | | | | +----+----+----+----+----+ | 5 | | | | | +----+----+----+----+----+ A C R O S S 1. D2 x 2 + 1 2. An oblong number. 3. D3 - A1 4. A3 + D5 5. D1 - A3 D O W N 1. NOT A2 2. NOT A1 3. A2 x 2 4. A5 - A2 5. A3 + D1