Answer: 
Step-by-step explanation:
For this exercise it is important to remember the multiplication of signs. Notice that:

In this case you have the following expression given in the exercise:

Then you can follow the steps shown below in order to solve it:
Step 1: You must solve the subtraction of the numbers 0,65 and 3,21. Then:

Step 2: Now you must find the product of the decimal numbers above. In order to do that you must multiply the numbers.
(As you can notice, both are negative, therefore you know that the product will be positive).
Then, you get that the result is the following:

Answer:
I think it's b I'm not sure I'm sorry if it's wrong
Answer:
37
Step-by-step explanation:
To start out, if you know that the digits add to 10, then the number must me around 46-37, as 28 and 82 wouldn't make sense, and 55 is a palindrome.
37-->73, 73-37=36.
Well, first you would estimate all the terms: 10.2 to 10, 2 to 2(keep the same), 3.7 to 4, and eight to eight.
So you have 10 x [(2 x 4) + 8]
then you would evaluate this expression using order of operations
10 x [(2 x 4) + 8]
10 x [8 + 8]
10 x 16
160