1. Find a nonzero number that written in binary system or decimal system "looks the same", i.e. has the same digits in their representation, written in the same order.

2. Find a number written in binary system that when read as a number in decimal system is five times smaller than the same number read as a decimal (notice that any binary number can be also interpret as a decimal, for example 111 can represent a binary number but also can be seen as one hundred and eleven - a decimal).

Treat this question like a puzzle, just try different numbers and this way guess the answer.

3a. The biggest whole number that can be represented in decimal system using only 2 digits is 99. What is the biggest whole number that can be presented in binary system using only 2 digits? Write your answer in decimal notation.

3b. What is the biggest whole number that can be presented in binary system using only 3 digits. Write your answer in decimal notation.

Please answer in 20 minutes and explain it too.