What are the digits based on the equations?

Let's solve the equations step by step: 1. 4th digit + 2nd digit = 10, 2. 3rd digit + 1st digit = 3, 3. 1st digit + 2nd digit = 9, 4. 4th digit + 1st digit = 5, 5. 4th digit + 3rd digit = 4. By solving these equations simultaneously: 4th digit = 2, 3rd digit = 2, 2nd digit = 8, 1st digit = 1. The digits are: 1, 8, 2, 2.