Answer:
1. Student 2
2. Student 2
3. Student 1 and Student 3
4. Student 2
5. Student 1
Explanation:
In order to answer the questions, you have to know the real number properties. These are:
Let A,B and C represent real numbers
Conmutative Properties:
A+B = B+A
A.B = B.A
Associative Properties:
(A+B) + C = A + (B+C)
(A.B).C = A. (B.C)
Distributive Property:
A. (B+C)= A.B + B.C
Identity Properties:
1.A=A
0+A=A
Hence, you have to identify the use of the properties in the processes of the three students.
For question 1:
The student 2 used the conmutative property A+ B = B+A because he wrote (6+9) as (9+6)
For question 2:
The student 2 used the associative property (A+B) + C = A + (B+C) because he wrote -9 + (9 + 6) - 42 as (-9 + 9) + 6 - 42
For question 3:
The student 1 used the distributive property because he wrote 5 - 2(4 + 9) - 11 as 5 - 2(4) - 2(9) -11. Also the student 3 because he wrote -4(10 + 4) - 32 - 2 ∙ 0 as -4(10) - 4(4) - 32 - 2 ∙ 0
For question 4:
The student 2 used the identity property 0+A=A because he wrote 0 + 6 + (-16) as 6 + (-16)
For question 5:
Just student 1, because the correct value of the expression of student 2 is:
-9 + (6+9) -42 = -9 + 15 -42 = -36
The correct value of the expression of student 3 is:
-4(14) - 32 - 2 ∙ 0 = -56 -32 = -88