What is the distance between point a of 2.5 and the origin on the number axis? What is the distance between point B of - 2.5 and the origin? What is the distance between two points AB?

What is the distance between point a of 2.5 and the origin on the number axis? What is the distance between point B of - 2.5 and the origin? What is the distance between two points AB?

2.5 2.5 5