Teething usually lasts 8 days which is 4 days before the tooth appears and 3 days after the tooth appears or erupts.
The tooth should push through the gums fully within 4 days but the baby can still be in pain for another few days.
The teeth are constantly erupting and coming through so the baby may or may not have all teeth push through at one time.
Sometimes they have more than one tooth come through at the same time and sometimes not.
It all depends on the baby.
You can give the baby some teething toys or teething biscuits to help with the teething pain.