# 2. Option 1.

Vasya took six cards with the numbers $513, 23, 5, 4, 46, 7$ written on them. He wants to arrange them in a row so that the resulting ten-digit number is the smallest possible. Write this number.
Answer: 2344651357.

Solution. If you place the card "23" at the beginning, the ten-digit number will start with the digit 2, and if you place another card, it will start with a larger digit. Therefore, you should start with the card "23". Next, the following digit should be as small as possible, so the second card should be "4" or "46". But if it's "46", the fourth digit will be 6, and if it's "4", the fourth digit can be 4, so the second position should be "4". Choose the card for the third position to make the next digit of the ten-digit number as small as possible - you need to choose "4". Next, between "513" and "5", you should choose "513", because if you place "5", the next smallest digit will be 5, which is greater than 1. Then place "5" because it is smaller than "7", and the last position is left for "7".