Alright, let's work through 3126 times 145 step by step
3126 × 145 = 145 × (3126)
+ 145 × 6 that results in 870
+ 145 × 20 that equals 2900
+ 145 × 100 that results in 14500
+ 145 × 3000 what gives us 435000

= 453270
