Are uncomfortable and have a fever or green or yellow mucus, you may want to keep them home until they feel better.
Have clear mucus and no fever but complain of a sore throat, you may want to call the doctor's office for an appointment to rule out strep throat but if children are awake and otherwise fine, you could send them to school that day.
Be ready for when children are too sick for school:
Before children are sick, write a list of babysitters for sick days if you cannot stay home from work.
Find out if there is ‘sick-care' in your city, town or area.
Save a few (paid or unpaid) personal days for your children when they are sick.
Make a plan with another parent in your school or neighborhood to take children when they are sick or need to be picked up early from school.