Alright, let's work through 3156 times 1264 step by step
3156 × 1264 = 1264 × (3156)
+ 1264 × 6 that results in 7584
+ 1264 × 50 resulting in 63200
+ 1264 × 100 producing 126400
+ 1264 × 3000 that equals 3792000

= 3989184
