Alright, let's work through 1398 times 4805 step by step
1398 × 4805 = 4805 × (1398)
+ 4805 × 8 yielding 38440
+ 4805 × 90 that is equal 432450
+ 4805 × 300 which equals 1441500
+ 4805 × 1000 producing 4805000

= 6717390
