Alright, let's work through 3551 times 121 step by step
3551 × 121 = 121 × (3551)
+ 121 × 1 that equals 121
+ 121 × 50 resulting in 6050
+ 121 × 500 what gives us 60500
+ 121 × 3000 resulting in 363000

= 429671
