Step 1 No *first digit 342*3=1026 289*2=578 .. Step 2 No+firs | Reasoning (Pre Mains level)

Step 1
No *first digit
342*3=1026
289*2=578
..

Step 2
No+first digit
1026+1=1027
578+5=583
...

Step 3
decreasing order
1027=7210
583=853
....

Step 4
7210=7^2+2^2+1^2+0^2=54
853=8^2+5^2+3^2=134
....

Step 5
Step 2+step 4
1027+54=1081
583+98=681
...….

Step 6
Odd*2
Even/2