Cloud Kicks wants to know the total value of all won Opportunities for Accounts and...

 The app builder should use Sum as the type of summary in the roll-up summary field. A Sum type of summary allows the app builder to calculate the total value of a numeric field from the child records related to a parent record by a master-detail relationship. The app builder can create a roll-up summary field on the Account object that sums the Amount field from the won Opportunities related to each Account. Count is not a valid type of summary, as it does not calculate the total value of a numeric field. A Count type of summary allows the app builder to count the number of child records related to a parent record by a master-detail relationship. Max is not a valid type of summary, as it does not calculate the total value of a numeric field. A Max type of summary allows the app builder to display the largest value of a numeric or date field from the child records related to a parent record by a master-detail relationship. Min is not a valid type of summary, as it does not calculate the total value of a numeric field. A Min type of summary allows the app builder to display the smallest value of a numeric or date field from the child records related to a parent record by a master-detail relationship.