These apples are 300 yen per kilo.

This luggage weighs more than 20 kilos.

This luggage weighs 20 kilos.

My father turns fifty this year.

He is fifty years old and still full of energy.

My birthday is on the fifteenth.

In chemistry class, I learned about the process of polymerization.

Through this chemical reaction, monomers polymerize to form polymers.

My room is twenty-five square meters.

Doublet is an important concept in linguistics.