It may not seem fair, but children whose parents are separated or divorced and who go back and forth between their parents’ homes really need to know both addresses and both phone numbers. I know that when you throw in cell phones and step-parents, that can be a lot of contact information—but it is important for safety’s sake that children know where they live and how to call—regardless of whose house they may be at.
For young children, it can be confusing and hard to keep both houses and phone numbers straight, but this is not excuse for them to not learn them. Consider putting both addresses and phone numbers on their belongings or coming up with some games where you practice writing or saying both addresses. Songs can be a very effective way to teach things to young children and even if you do not fancy yourself a songwriter, you can come up with a little ditty (perhaps sung along to a familiar tune) that includes information about “mom’s house” and “dad’s house.” If you can make it rhyme, all the better for helping a child to remember what can be tough information to hold on to.
It is important that children know how to get in touch with either parent in case of an emergency and to know as much as possible regarding directions and how to get to each house, as well as each parent’s work schedules and contact information there. This way, a child or the responsible adult in charge can reach whichever parent is closest in case of an emergency without having to look up paperwork which may or may not be available. Periodically “quiz” your child and check in to make sure he or she knows the contact information for both parents and both houses, even if you assume that he or she does.