Jennifer likes to play tennis. Last year, Jennifer played tennis $19$ days in each of the months of January, February, March, and April, she played tennis $20$ days in each of the months of May, June, July, and August, and she played tennis $21$ days in each of the months of September, October, November, and December. How many days did Jennifer play tennis last year?

Each of the walls of a room with square dimensions has been built with two pieces of sheetrock, a smaller one and a larger one. the length of all the smaller ones is the same and is stored in the variable small. similarly, the length of all the larger ones is the same and is stored in the variable large. write a single expression whose value is the total area of this room. do not use any method invocations.

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?

Arectangular courtyard is 12 feet long and 8 feet wide. a tile is 2 feet long and 2 feet wide. how many tiles are needed to cover the courtyard?