-3 2/5 - 5/6 = -127/30
-2/3 + 6 1/8 = 107/24
9. increase
10. decrease
11. increase
12. decrease
13. decrease
14. decrease
15. increase
16. increase
Answer: 
Step-by-step explanation:
<h3>
The complete exercise is: "A rectangular yard is 20 ft by 15 ft. The yard is cover with grass except for 8.5 feet square flower garden. How much grass is in the yard?"</h3><h3 />
The area of a rectangle can be calculated with the following formula:

Where "l" is the lenght of the rectangle and "w" is the width.
Based on the data given in the exercise, you can identify tha the length and the width of the rectangular yard are:

Then, you can substitute these values into the formula and then evaluate in order to find the area of the entire yard:

The area of the flower garden which is an square, can be calculated with this formula:

Where "s" is the side length.
In this case you know that:

Then the area of the flower garden is:

<em> </em>Since this is not covered with grass, you need to subtract both areas calculated above in order to find the surface covered with grass in the yard.
This is:

412 divide by 84 how many times can 84 go into 412
84 can go into 412, 4 times and four time 84 equals
331, then continue dividing 84 into the number you obtain by sutracting the number before and the multiple of 84 and x
your answer will be 4.904