The California High School Exit Exam: Math (CAHSEE) consists of 92 questions  80 of those questions actually count toward your score. The following areas are covered (not necessarily in this order):

Number Sense (NS), 14 questions

Statistics, Data Analysis, Probability (P), 12 questions

Measurement and Geometry (MG), 17 questions

Algebra and Functions (AF), 17 questions

Mathematical Reasoning (MR), 8 questions

Algebra I (AI), 12 questions
These are the questions that count on your score (80 questions, total). You will also be asked 12 trial questions for future tests, for a total of 92 questions on the whole exam.
Because this is a new test, the number of questions and the types of questions might be adjusted slightly in later tests. Also note that the trial questions can be scattered anywhere on the exam.
The actual CAHSEE Math exam is given in two sessions — 46 questions in each session. Although there is no time limit on the test, the approximate working times are estimated as one hour and 30 minutes for each session.
Both sessions will be administered on the same day with a break between the two sessions. You should be allowed to take the time you need within the school day to finish the exam.