What two-digit numbers can be written using only the numbers 0 and 1?

Solution:
10; eleven;
Answer: 10; eleven.
Explanations. By enumerating options using the numbers 0 and 1, you can get the following options: 00; 01; 10; 11 (the first digit from the first, the first from the second, the second from the first and the second from the second), but the first two numbers are not two-digit. The task requires only two-digit numbers, which means that only numbers – 10 and 11 – will be answered.