Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

The system uses only two : zero and one. It is used in computers and computer-based , such as smartphones and [?] .
We call to each digit . We can express four different numbers with just bits