Alright, let's work through 8378 times 8175 step by step
8378 × 8175 = 8175 × (8378)
+ 8175 × 8 what gives us 65400
+ 8175 × 70 that results in 572250
+ 8175 × 300 which equals 2452500
+ 8175 × 8000 that equals 65400000

= 68490150
