My birthday is on the fourteenth.

My father is forty years old.

He ate one apple.

This is a 六角四片四角孔ねじれ正多面體, in other words, a muoctahedron.

We need to think about this problem in multiple dimensions.

A positive-definite matrix is an important concept in linear algebra.

There are times when we perform calculations with the haversine in trigonometry.

He drew an equilateral triangle shape.

He is an expert in orthoepy, teaching pronunciation.

This orthophoto shows the details of the terrain very clearly.