Filter Wizard doesn't work with numbers (Excel) - foundation training Lesson 9

I’m having the exact same problems:

1. filtering on age < 30 does not work: I get either only the header row (Keep 1 < 30) or all rows inclusive the header row (Remove 1 < 30)

example:
data:
image
filter:
image
results to:
image

digging deeper: ages do not correspond to original ages - what is going on???

2. filtering on name begins with "AN" works

example:
data:
same as above
filter:
image
results to:
image

digging deeper: ages do not correspond to original ages - what is going on???

3. not able to get downloaded example working

as mentioned in Lesson 9 - Excel and Data Tables - Workflows.zip Error in downloaded xaml 'errors in the xaml' - #7 by charliefik

How can I filter on numbers?
Why are the ages changing?
(and how can I get downloaded example working?)

Anyone any suggestions?
Thanks!