1. ////// WORKIGN CODE ////
2.  
3. var firstVar , secondVar , thridVar , forthVar;
4.  
5. firstVar = prompt('Enter The First Value of Series!!!');
6. secondVar = prompt(firstVar + ',');
7. thridVar = prompt(firstVar + ',' +secondVar + ',');
8. forthVar = prompt(firstVar + ',' +secondVar + ',' + thridVar + ',');
9.  
10.  
11. var check ;
12.  
13. if (  secondVar - firstVar === forthVar - thridVar  )
14.     {
15.         check = 0;
16.     }
17. else if(secondVar / firstVar === forthVar / thridVar )
18.        
19.     {
20.         check = 2;
21.     }
22. else if(secondVar * firstVar === forthVar * thridVar )
23.     {
24.         check = 3;
25.     }
26. else if(secondVar + firstVar === forthVar + thridVar )
27.     {
28.         check = 1;
29.     }
30.  
31.  
32.  
33. switch ( check ) {
34.     case 0:
35.         console.log('This series is maid by Substion tech:');
36.         break;
37.     case 1:
38.         console.log('This series is maid by Addition tech:');
39.         break;
40.     case 2:
41.         console.log('This series is maid by Division tech:');
42.         break;
43.     case 3:
44.         console.log('This series is maid by Multiplication tech:');
45.         break;
46.     default:
47.         console.log('Invalid Series!!!');
48. }
49.  
50.  
51.  
52. //////////// Not Working CODE.
53.  
54.  
55. var firstVar , secondVar , thridVar , forthVar;
56.  
57. firstVar = prompt('Enter The First Value of Series!!!');
58. secondVar = prompt(firstVar + ',');
59. thridVar = prompt(firstVar + ',' +secondVar + ',');
60. forthVar = prompt(firstVar + ',' +secondVar + ',' + thridVar + ',');
61.  
62.  
63. var check ;
64.  
65. switch (
66.    
67. (secondVar - firstVar === forthVar - thridVar ? 0 : null ) ||
68. (secondVar + firstVar === forthVar + thridVar ? 1 : null)  ||
69. (secondVar / firstVar === forthVar / thridVar ? 2 : null )  ||
70. (secondVar * firstVar === forthVar * thridVar ? 3 : null )
71.  
72.  
73. ) {
74.     case 0:
75.         console.log('This series is maid by Substion tech:');
76.         break;
77.     case 1:
78.         console.log('This series is maid by Addition tech:');
79.         break;
80.     case 2:
81.         console.log('This series is maid by Division tech:');
82.         break;
83.     case 3:
84.         console.log('This series is maid by Multiplication tech:');
85.         break;
86.     default:
87.         console.log('Invalid Series!!!');
88. }
89.  
90.