Alright, let's work through 1855 times 9839 step by step
1855 × 9839 = 9839 × (1855)
+ 9839 × 5 producing 49195
+ 9839 × 50 that equals 491950
+ 9839 × 800 that is equal 7871200
+ 9839 × 1000 that equals 9839000

= 18251345
