You could do it this way (example including just 2 of the columns but you can obviously add more):
fig, ax = plt.subplots(figsize=(12,6), ncols=2)
df_num["backers_count"].plot.box(ax=ax[0])
df_num["converted_pledged_amount"].plot.box(ax=ax[1]);
...or with Seaborn:
fig, ax = plt.subplots(figsize=(12,6), ncols=2)
sns.boxplot(data=df_num, y="backers_count", ax=ax[0])
sns.boxplot(data=df_num, y="converted_pledged_amount", ax=ax[1]);
If you want to display them in a grid of, say 3 rows and 3 columns then you can change the ncols=2
bit to nrows=3, ncols=3
, and then instead of ax=ax[0]
, ax=ax[1]
etc you would write ax=ax[0,0]
, ax=ax[0,1]
etc