Let's get this math done. We have 810 and we're going to multiply it by 17. This is the same as taking 810 and adding it to itself 17 times.
Step 1: 0 + 810 = 810
Step 2: 810 + 810 = 1620
Step 3: 1620 + 810 = 2430
Step 4: 2430 + 810 = 3240
Step 5: 3240 + 810 = 4050
Step 6: 4050 + 810 = 4860
Step 7: 4860 + 810 = 5670
Step 8: 5670 + 810 = 6480
Step 9: 6480 + 810 = 7290
Step 10: 7290 + 810 = 8100
Step 11: 8100 + 810 = 8910
Step 12: 8910 + 810 = 9720
Step 13: 9720 + 810 = 10530
Step 14: 10530 + 810 = 11340
Step 15: 11340 + 810 = 12150
Step 16: 12150 + 810 = 12960
Step 17: 12960 + 810 = 13770

So, 810*17 = 13770