Copy and complete each of the Diamond Problems below. The pattern used in the Diamond Problems is shown below.

1. 

   Hint (a):

   What are the product and sum of $2.4$ and $1.5$?

2. 

   Hint (b):

   $? (0.6) = 4.2$

   Answer (b):

   

3. 

   Hint (c):

   $3.1 + ? = 11.1$

4. 

   Hint (d):

   Which two numbers have a product of $-49$ and a sum of $0$?

   More Help (d):

   Since the sum is $0$, one number must be negative and one must be positive, but both numbers must have the same magnitude.

   Answer (d):