Final answer:
The ideal amount of time to arrive early to a substitute teaching assignment is at least 15 minutes before the bell rings.
Step-by-step explanation:
When substitute teaching, it is best to arrive at least 15 minutes before the bell rings. This allows you enough time to familiarize yourself with the classroom and any lesson plans left by the regular teacher. It also gives you a chance to greet students as they arrive and establish a positive rapport with them. Being early shows professionalism and preparedness, and it allows for a smooth transition into the classroom environment.