This is a troublesome spot for students - that darn 'th' sound in English. We use it so much and English learners can't produce it easily. So, we worked on dates in level 1 classes.
These numbers go beyond dates though. When we talk about floor levels in a building, streets and avenues, the position of someone or something in a line.
Practice with students by pointing out when you're using these types of numbers so that they increase their listening awareness.