I think you are thinking of the phrase  the other way around , which does essentially mean the opposite, but in a specific way. The specific nature of the other way around is that it means that doing what you say in the opposite direction is correct, not necessarily the exact opposite.
Once kittens reach 4 weeks of age, their mother usually begins to wean them off milk and onto solid foods. Because the weaning process can take up to six weeks, purchase a small amount of kitten milk replacement formula and mix it into your kitten's food during his first two weeks with you.
While waiting for the shelter to have room for your kittens you should: Provide proper nourishment. Kittens 5 weeks old can be started on wet kitten food â sometimes adding a kitten replacer (available at feed/pet stores and veterinarians offices) to the wet food can help a kitten who is a little undernourished. Kittens 6 weeks and older can eat wet or dry kitten food.