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.
Over the first 3 months, the baby gradually sleeps for longer periods. By the third or fourth month, most babies sleep for their longest period (up to 7 to 8 hours) during the night and develop set nap times. You can help your baby-and yourself-sleep better. When your baby is getting sleepy, put your baby in his or her crib in a quiet, darkened room. 2  This will help your baby learn to go to sleep in his or her crib. 3  Don't rock your baby to sleep after about age 4 to 6 months. 4  Rock your baby, but lay the baby down to sleep while he or she is drowsy but still awake.