Help to Install Python on Ubuntu

[gulshannegi]

I am trying to install Python 3.9 on my Ubuntu OS, I try to install Python in the following manner
sudo apt-get install python3.9
after seems installed I tried checking the version:
python -V
However, this input returns:
-bash: python: command not found
It seems like Python versions don't fully install.
Can anyone help me for installing the Python on Ubuntu

[mikeshinn]

On many distros, the python binary will be named after the version, for example the binary name may be:

python3.9

Instead of python.