Install brew (https://brew.sh/) if you don't have it already.

Now install Python3 with brew: brew install python3

Now install numpy and tensorflow with pip:

sudo python3 -m pip install --upgrade numpy matplotlib tensorflow==1.15

IDE recommendation PyCharm:

https://www.jetbrains.com/pycharm/download/

Open source alternative spyder:

sudo python3 -m pip install --upgrade spyder pyqt5 rope_py3k

If you have trouble starting spyder, you might need to install qt5 also with brew: brew install pyqt5