Soluciones:

NORTHWARD HO The bear was a polar bear and the spot he chose
to take his nap was precisely the North Pole.

A CLASSIC RIDDLE: Man. As a baby, he crawls on hands and feet, as an adult he walks on his two legs, and in old age, he walks with a cane.

LEAP YEAR? All twelve, naturally.

BABY BOOM 15,000.

HARMFUL TO YOUR HEALTH: Seven. First he rolls 6 cigarettes and smokes them, leaving him with 7 butts with which to roll a seventh cigarette.

VIVE LA DIFFERENCE If you really don't know, please don't invite me for dinner.

THE RIGHT TIME: Richard's watch will display the right time twice in every twenty-four hour period, that is, 1,440 times more often than Robert's.