Masato is my best friend.

He practices every day to learn the correct Chinese pronunciation of characters.

Orthoclase is a type of mineral, mainly found in granite.

Hiragana is one of the characters in Japanese.

It's very interesting to learn about the history of the Shōkei era.

I am a believer in Orthodoxy.

Calculating the value of secant, one of the trigonometric functions, is difficult.

The calculation of versine is a part of trigonometry.

This 正數 is the same as what I learned in school.

Positive charge is a type of electric charge of matter.