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.
1 The child has just started rolling and it is only occasionally disrupting sleep. 2  Put baby down in the usual position (so on back for a back sleeper, tummy for a tummy sleeper) and leave. 3  If baby rolls over and is upset, always make sure to wait a minimum of 10-15 minutes before deciding if an intervention is required.