Răspuns:
1. a) 4, 40, 990, 4900, 49900.
b) 44009, 9409, 999, 949, 499.
2. a) 3132, 121322, 321312.
b) 312213, 123321, 122311, 12123.
3. a) 103301, 130302, 204103, 204402.
b) 402204, 301103.
4. a) 75057, 700777, 705007, 705070.
b) 770750, 707500, 707005.
