What is 17.8 + 12.115 in sig fig

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

Is laundry detergent an acid or a base?

Which of these is an example of pseudoscience? a) predicting the time of sunrise based on data on position of earth b) predicting the date of the moon phases based on data on position of earth c) predicting eclipses based on the position of the sun and the moon d) predicting future events in a person's life based on the position of the moon