Alright, let's work through 1640 times 9654 step by step
1640 × 9654 = 9654 × (1640)
+ 9654 × 0 that is equal 0
+ 9654 × 40 which equals 386160
+ 9654 × 600 which equals 5792400
+ 9654 × 1000 what gives us 9654000

= 15832560
