Let's get this math done. We have 825 and we're going to multiply it by 28. This is the same as taking 825 and adding it to itself 28 times.
Step 1: 0 + 825 = 825
Step 2: 825 + 825 = 1650
Step 3: 1650 + 825 = 2475
Step 4: 2475 + 825 = 3300
Step 5: 3300 + 825 = 4125
Step 6: 4125 + 825 = 4950
Step 7: 4950 + 825 = 5775
Step 8: 5775 + 825 = 6600
Step 9: 6600 + 825 = 7425
Step 10: 7425 + 825 = 8250
Step 11: 8250 + 825 = 9075
Step 12: 9075 + 825 = 9900
Step 13: 9900 + 825 = 10725
Step 14: 10725 + 825 = 11550
Step 15: 11550 + 825 = 12375
Step 16: 12375 + 825 = 13200
Step 17: 13200 + 825 = 14025
Step 18: 14025 + 825 = 14850
Step 19: 14850 + 825 = 15675
Step 20: 15675 + 825 = 16500
Step 21: 16500 + 825 = 17325
Step 22: 17325 + 825 = 18150
Step 23: 18150 + 825 = 18975
Step 24: 18975 + 825 = 19800
Step 25: 19800 + 825 = 20625
Step 26: 20625 + 825 = 21450
Step 27: 21450 + 825 = 22275
Step 28: 22275 + 825 = 23100

So, 825*28 = 23100