Alright, let's work through 3243 times 5703 step by step
3243 × 5703 = 5703 × (3243)
+ 5703 × 3 what gives us 17109
+ 5703 × 40 that is equal 228120
+ 5703 × 200 which equals 1140600
+ 5703 × 3000 giving us 17109000

= 18494829
