title: Installing numpy on Ubuntu without pip/anaconda
body: <p>Without using <code>anaconda or pip</code>, while installing <code>numpy</code> on Ubuntu and printing numpy version, i get this : </p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/lib/python3/dist-packages/numpy/core/__init__.py", line 17, in &lt;module&gt;
      from . import multiarray
    File "/usr/lib/python3/dist-packages/numpy/core/multiarray.py", line 14, in &lt;module&gt;
      from . import overrides
    File "/usr/lib/python3/dist-packages/numpy/core/overrides.py", line 7, in &lt;module&gt;
      from numpy.core._multiarray_umath import (
  ModuleNotFoundError: No module named 'numpy.core._multiarray_umath'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "basicVersions.py", line 2, in &lt;module&gt;
      import numpy as np
    File "/usr/lib/python3/dist-packages/numpy/__init__.py", line 142, in &lt;module&gt;
      from . import core
    File "/usr/lib/python3/dist-packages/numpy/core/__init__.py", line 47, in &lt;module&gt;
      raise ImportError(msg)
  ImportError: 
  
  IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!
  
  Importing the numpy c-extensions failed.
  - Try uninstalling and reinstalling numpy.
  - If you have already done that, then:
    1. Check that you expected to use Python3.7 from "/usr/bin/python3.7",
       and that you have no directories in your PATH or PYTHONPATH that can
       interfere with the Python and numpy version "1.17.4" you're trying to use.
    2. If (1) looks fine, you can open a new issue at
       https://github.com/numpy/numpy/issues.  Please include details on:
       - how you installed Python
       - how you installed numpy
       - your operating system
       - whether or not you have multiple versions of Python installed
       - if you built from source, your compiler versions and ideally a build log
  
  - If you're working with a numpy git repository, try `git clean -xdf`
    (removes all files not under version control) and rebuild numpy.
  
  Note: this error has many possible causes, so please don't comment on
  an existing issue about this - open a new one instead.
  
  Original error was: No module named 'numpy.core._multiarray_umath'
  </code></pre>
  
  <p>On all the forums, installation steps given are in context of pip/anaconda. I don't find lot of reference with installation on Ubuntu via apt/apt-get. This looked like installation error, so i tried this as well, but no luck. Please help! </p>
  
  <pre><code>sudo apt install numpy
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  E: Unable to locate package numpy
  ~/python$ sudo apt install python3-numpy
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  python3-numpy is already the newest version (1:1.17.4-5ubuntu3).
  0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
  </code></pre>
  
  <p>Could this be python version issue?
  This was the code I was trying : </p>
  
  <pre><code>import sys
  import numpy as np
  import matplotlib
  
  print("Python: ", sys.version)
  print("Numpy: ", np.__version__)
  print("Matplotlib: ", matplotlib.__version__)
  </code></pre>