This puzzle consists completely of binary numbers, so all the characters needed to fill in the squares will be 0s or 1s. The crossnumber is a 5x5 square grid, with 5 digits, e.g., 1 will be 00001, 2 will be 00010, and 4, 00100.
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

Posted by K Sengupta on 2022-08-31 11:03:39