Can people with tall grandparents and short parents grow taller than their parents? what are the odds of this happening?

Depends: If the parents growth was kept from reaching its potential from nutritional or medical problems it would be more likely that their kids could be taller than predicted by their height. In most normal settings a kid will reach the average height of both parents plus 2.5" if male and less 2.5" if female. Odds are undefined-too many variables.