There is a communal letterbox in our apartment.

My child attends a supplementary school every Saturday.

In set theory, the symmetric difference indicates the difference between two sets.

The mythology of Oyamatsumi is particularly interesting among Japanese myths.

She has trypophobia, and feels discomfort when she sees things with many holes like beehives or corals.

He understands the meaning of the proverb 'Teaching is half learning', which means that teaching leads to one's own learning.

He always keeps in mind the phrase 'If one learns without thinking, it is a waste.'

The Riemann sum is a method for approximately calculating the integral of a function.