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.
If your baby startles awake when placed down for sleep on his back... put him on his tummy!... and don't worry about it! My 5 week old has always slept on her tummy and now sleeps for 5 hours at a time.lso, he's been able to move his head from side to side since he was a few days old, believe it or not. So that he and I can rest and not go insane, he sleeps near me on his stomach. He is healthy and happy. With my generation, they said DON'T but the babies on their backs to sleep...now they want them on their backs.