1, and the last three digits are one digit, two digits and three digits respectively. Their average value is 170. Please write the numbers (5), (7 )9 and (4)26 in brackets.

2. There are three classes in the fourth grade of Guangming Road Primary School, class A and class B ***85 days, class B and class C ***95 students, and class C *** 106 students. How many people are there in Class A, Class B and Class C?

Class a, class b and class c = (85+95+106)/2 =143 students.

Class C = 143-85=58 people.

Class A = 143-95=48 people.

Class b = 143- 106=37 people.