Alright, let's work through 3943 times 415 step by step
3943 × 415 = 415 × (3943)
+ 415 × 3 which equals 1245
+ 415 × 40 that equals 16600
+ 415 × 900 that equals 373500
+ 415 × 3000 that is equal 1245000

= 1636345
