Alright, let's work through 6436 times 4021 step by step
6436 × 4021 = 4021 × (6436)
+ 4021 × 6 that results in 24126
+ 4021 × 30 that is equal 120630
+ 4021 × 400 producing 1608400
+ 4021 × 6000 what gives us 24126000

= 25879156
