How to go in to interactive mode?

Answer 1

On Linux you may need to press Tab after 'python' at the prompt and then complete the name. Python 3 is installed as a separate binary (with a longer name) when 2.x already exists.

An example from my system:

$ python (press tab)
python python-android5

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If you just need an interpreter in addition to your question:

QPython3 is fine for Android.

Online (editor up top, interactive below)
https://repl.it/languages/python3

Answer 2

just type this on the terminal
>> python

Answer 3

type python3 on your command prompt