Alright, let's work through 1720 times 426 step by step
1720 × 426 = 426 × (1720)
+ 426 × 0 what gives us 0
+ 426 × 20 giving us 8520
+ 426 × 700 that equals 298200
+ 426 × 1000 yielding 426000

= 732720
