asÂ·soÂ·ciÂ·aÂ·tive property. The property of addition and multiplication which states that a difference in the grouping of numbers being added or multiplied will not change the result, as long as the order of the numbers stays the same. For example, 3 + (4 + 5) is equal to (3 + 4) + 5. See also commutative property, distributive property. 1  Facebook.
The most common recommendation is to initially place infants to sleep on their backs for the first 12 months. However, when the infant is able to roll over on their own in to the sleep position of his/her choice than it is fine to leave the baby in that position. My children are now 29, 27, 24, and 11.
Note: These recommendations are for healthy babies up to 1 year of age. A very small number of babies with certain medical conditions may need to be placed to sleep on their stomachs. Your babyâs doctor can tell you what is best for your baby. What you can do? Place your baby to sleep on his back for every sleep. Babies up to 1 year of age should always be placed on their backs to sleep during naps and at night. However, if your baby has rolled from his back to his side or stomach on his own, he can be left in that position if he is already able to roll from tummy to back and back to tummy. If your baby falls asleep in a car safety seat, stroller, swing, infant carrier, or infant sling he should be moved to a firm sleep surface as soon as possible. Place your baby to sleep on a firm sleep surface.