(2) The four-digit number 8()9 () is divisible by both 8 and 9. What is this four-digit number?
(3) The sum of 30 consecutive natural numbers is 2265. What is the sum of all even numbers in these 30 natural numbers?
(4) The sum of two times of one prime number and three times of another prime number is exactly 100. What are these two prime numbers?
(5) 1 The probability that the ball is just a black ball is 1/3, that is,
A. If you touch the ball three times, you will definitely hit the black ball 1 time.
B, if you touch the ball three times, you must have missed the black ball 1 time.
C, if you touch the ball many times, there will be 1 black ball touch the ball every three times on average.
D, there are 1 black balls and 2 balls of different colors in the bag.
(6) in triangle ABC, ∠ 1 = ∠ 2, ∠ c >; ∠B, e is a point above AD, and EF⊥BC is in F.
(1) Try to explore the relationship between ∠DEF and ∠ b, ∠ c.
(2) As shown in Figure (2), when point E is on the extension line of AD, other conditions remain unchanged. Is the conclusion you explored in (1) still valid? And give reasons.