1. What about −(−6) ?
What quantity is in the box?

2. What quantity is now in the box?
+ 6
What quantity is now in the box?

3. What quantity is now in the box?
− 6
What quantity is now in the box?

4. What quantity is now in the box?
+ 6
− 6
What quantity is now in the box?

5. What quantity is now in the box?
−(−6) means remove −6
+ 6
− 6
What quantity is now in the box?
Therefore −(−6) means remove −6 this gives a + 6
Therefore −(−6) = + 6

6. What about +(− 6) ?
What quantity is in the box?

7. What quantity is now in the box?
+ 6
What quantity is now in the box?

8. What quantity is now in the box?
− 6
What quantity is now in the box?

9. What quantity is now in the box?
+ 6
− 6
What quantity is now in the box?

10. What quantity is now in the box?
+(−6) means add −6
+ 6
− 6
− 6
What quantity is now in the box?
Therefore +(−6) means add −6 this gives a −6
Therefore +(−6) = − 6

11. What about −(+ 6) ?
What quantity is in the box?

12. What quantity is now in the box?
+ 6
What quantity is now in the box?

13. What quantity is now in the box?
− 6
What quantity is now in the box?

14. What quantity is now in the box?
+ 6
− 6
What quantity is now in the box?

15. What quantity is now in the box?
−(+6) means remove +6
+ 6
− 6
What quantity is now in the box?
Therefore −(+6) means remove +6 this gives a −6
Therefore −(+6) = − 6