Thanks Adam,
Here NinjaDevo gave a wonderful answer for 36
https://web2.0calc.com/questions/theanswertotheexpression36locatedonahorizontalnumberline
I pulled this straight out of our sticky notes under "Great answers to learn from"
So with any addition or subtraction you
1) start on the number line at the first number.
2) Go left if you are subtracting (just like NinjaDevo did)
3) Go right if you are adding
How many distinct, nonequilateral triangles with a perimeter of 60 units have integer side lengths $a$, $b$, and $c$ such that $a$, $b$, $c$ is an arithmetic sequence?
let the sides by a, a+d, a+2d where a and d are both positive integers and d>0
\(a+a+d+a+2d=60\\ 3a+3d=60\\ a+d=20\\ \)
d  a  a+d  a+2d  Is the sum of the two little numbers bigger than the 3rd one. If not then it cannot be a triangle

19  1  20  39  no 
18  2  20  38  no 
17  3  
16  4  
15  5  n  
14  6  20  34  no 
13  7  n  
12  8  n  
11  9  20  31  no 
10  10  20  30  no 
9  11  20  yes 1  
8  12  20  28  yes 2 
7  13  20  27  y 3 
6  14  20  26  4 
5  15  20  25  5 
4  16  20  24  6 
3  17  20  23  7 
2  18  20  22  8 
1  19  20  21  9 
9 of the combinations work :)