Answer:
14980
Explanation:
4 2 8
x
3 5
-----------
2 1 4 0 ---> 428 x 5
1 2 8 4 ---> 428 x 3 but since 3 is in the 10s place we shift by 1
--------------- to the left. You can think of that 1248 as 12480
1 4 9 8 0 --> add the two rows
Hope that helps. I tried my best to explain :)