OK, let's crack this. We're given 812 and our task is to multiply it by 26. Essentially, we'll be adding 812 to itself 26 times.
Step 1: 0 + 812 = 812
Step 2: 812 + 812 = 1624
Step 3: 1624 + 812 = 2436
Step 4: 2436 + 812 = 3248
Step 5: 3248 + 812 = 4060
Step 6: 4060 + 812 = 4872
Step 7: 4872 + 812 = 5684
Step 8: 5684 + 812 = 6496
Step 9: 6496 + 812 = 7308
Step 10: 7308 + 812 = 8120
Step 11: 8120 + 812 = 8932
Step 12: 8932 + 812 = 9744
Step 13: 9744 + 812 = 10556
Step 14: 10556 + 812 = 11368
Step 15: 11368 + 812 = 12180
Step 16: 12180 + 812 = 12992
Step 17: 12992 + 812 = 13804
Step 18: 13804 + 812 = 14616
Step 19: 14616 + 812 = 15428
Step 20: 15428 + 812 = 16240
Step 21: 16240 + 812 = 17052
Step 22: 17052 + 812 = 17864
Step 23: 17864 + 812 = 18676
Step 24: 18676 + 812 = 19488
Step 25: 19488 + 812 = 20300
Step 26: 20300 + 812 = 21112

So, 812*26 = 21112