did you run the block of code where you import numpy, pandas and matplotlib?
if they are in different blocks you need to execute the first one first, then the second.
No, not really. I was just giving you an example of how each cell gets a number in the order it was run. You need to run them in order.
Go back to your original code. Run the import cell first. Then run the next cell. The import cell should get a [1] indicating it was run first. The second cell should have a [2] indicating it was run second.
as you can see in this screenshot, when you use print(pd) you dont get the error that pd is not defined, because you ran the block of code that imports pandas as pd before you ran the print(pd) one.
you should do the same with your challenge.