Alright, let's work through 7638 times 6745 step by step
7638 × 6745 = 6745 × (7638)
+ 6745 × 8 what gives us 53960
+ 6745 × 30 which equals 202350
+ 6745 × 600 resulting in 4047000
+ 6745 × 7000 resulting in 47215000

= 51518310
