Alright, let's work through 3970 times 5138 step by step
3970 × 5138 = 5138 × (3970)
+ 5138 × 0 what gives us 0
+ 5138 × 70 resulting in 359660
+ 5138 × 900 yielding 4624200
+ 5138 × 3000 that equals 15414000

= 20397860
