9347
You need to multiply the digits of the first number with the reverse of the digits in second number as shown below for the first equation;
8 x 2 = 16
6 x 4 = 24
3 x 5 = 15
8 x 7 = 56
Now take the first digit of all the results and hence we get;
8638 + 7542 = 1215
Similarly for the second equation we get;
5 x 8 = 40
5 x 6 = 30
8 x 4 = 32
9 x 2 = 18
After taking the first digits we get;
5589 + 2468 = 4331
Then;
1357 + 1919 = 9347
1 x 9 = 9
3 x 1 = 3
5 x 9 = 45
7 x 1 = 7
Answer = 9347
