Alright, let's work through 3993 times 3432 step by step
3993 × 3432 = 3432 × (3993)
+ 3432 × 3 that equals 10296
+ 3432 × 90 that results in 308880
+ 3432 × 900 that is equal 3088800
+ 3432 × 3000 giving us 10296000

= 13703976
