There are several ticket types.
1. Base ticket. Gets you into any ONE of Disney's four theme
parks (Magic Kingdom, Animal Kingdom, Epcot, Disney's Hollywood
Studios) per day.
2. Park Hopper. Allows you to enter more than one of the four
theme parks per day. Prices can change, but currently there is a flat
$50 charge per ticket. For the same $50 you can add Hopping to a 1-day
ticket or a 10-day ticket.
3. Water Park Fun & More add-on. This is another flat-fee option
that can be added to either a base ticket or a Park Hopper. The WPF&M
option allows you a specific number of admissions to the Disney water
parks or DisneyQuest. The number of WPF&M admissions you receive is
equal to the number of days of theme park ticket you have. For example,
if you have a four-day base ticket and purchase the WPF&M add-on,
you will be given four admissions to the water parks or DQ.
Currently, the WPF&M add-on costs $50 per ticket. The rate is the
same if you have a 1-day theme park ticket or a 10-day theme park
ticket.
Theme park admissions and WPF&M admissions are unrelated. To answer
your specific question, if you have a base ticket with the WPF&M
add-on, you can go to both ONE theme park and a water park or DQ in the
same day. If you have a Park Hopper ticket you could go to two theme
parks in a day, but not to a water park or DQ. If you have the
Park Hopper with the WPF&M add-on, you can go to more than one
theme park AND a water park or DQ.
You can find related questions
HERE,
HERE, and
HERE.