Alright, let's work through 3996 times 8656 step by step
3996 × 8656 = 8656 × (3996)
+ 8656 × 6 producing 51936
+ 8656 × 90 that is equal 779040
+ 8656 × 900 what gives us 7790400
+ 8656 × 3000 that equals 25968000

= 34589376
