Problem 4. Mira used the digits $3,7,1,9,0$ and 4 to form the largest and smallest six-digit numbers using each digit exactly once, and then reduced their difference by 9 times. What number did Mira get?
Solution. The largest six-digit number composed of the given digits, using each digit exactly once, is the number 974310, and the smallest is the number 103479. When their difference $974310-103479=870831$, is divided by 9, the result is $870831: 9=96759$.

Problem 5. Four boys, Andrej, Bojan, Vasko, and Gjorce, are collectors of postage stamps. Andrej has as many stamps as Bojan and Vasko together, Gjorce has five times fewer stamps than Andrej, and Bojan has four times more stamps than Vasko. How many stamps does each of the boys have if together they have 5016 postage stamps?