Question 1: Discount sale.
Answer: 400 yuan.
Question 2: Engineering and travel issues
Answer: 4 hours.
Question 3: savings problem
Answer: (1)800( 1+p%)
(2)B
Question 4: Calendar equation problem
Answer: (1) 7, 14, 2 1 none.
(2) 16, 17,23,24
Question 5: Chart problem
Answer: 20
Question 6: Area problem
Answer: 738
Question 7: Numbers.
Answer: 7 1
Children's poor academic performance is due to their failure to master learning methods.