OK, let's crack this. We're given 405 and our task is to multiply it by 61. Essentially, we'll be adding 405 to itself 61 times.
Step 1: 0 + 405 = 405
Step 2: 405 + 405 = 810
Step 3: 810 + 405 = 1215
Step 4: 1215 + 405 = 1620
Step 5: 1620 + 405 = 2025
Step 6: 2025 + 405 = 2430
Step 7: 2430 + 405 = 2835
Step 8: 2835 + 405 = 3240
Step 9: 3240 + 405 = 3645
Step 10: 3645 + 405 = 4050
Step 11: 4050 + 405 = 4455
Step 12: 4455 + 405 = 4860
Step 13: 4860 + 405 = 5265
Step 14: 5265 + 405 = 5670
Step 15: 5670 + 405 = 6075
Step 16: 6075 + 405 = 6480
Step 17: 6480 + 405 = 6885
Step 18: 6885 + 405 = 7290
Step 19: 7290 + 405 = 7695
Step 20: 7695 + 405 = 8100
Step 21: 8100 + 405 = 8505
Step 22: 8505 + 405 = 8910
Step 23: 8910 + 405 = 9315
Step 24: 9315 + 405 = 9720
Step 25: 9720 + 405 = 10125
Step 26: 10125 + 405 = 10530
Step 27: 10530 + 405 = 10935
Step 28: 10935 + 405 = 11340
Step 29: 11340 + 405 = 11745
Step 30: 11745 + 405 = 12150
Step 31: 12150 + 405 = 12555
Step 32: 12555 + 405 = 12960
Step 33: 12960 + 405 = 13365
Step 34: 13365 + 405 = 13770
Step 35: 13770 + 405 = 14175
Step 36: 14175 + 405 = 14580
Step 37: 14580 + 405 = 14985
Step 38: 14985 + 405 = 15390
Step 39: 15390 + 405 = 15795
Step 40: 15795 + 405 = 16200
Step 41: 16200 + 405 = 16605
Step 42: 16605 + 405 = 17010
Step 43: 17010 + 405 = 17415
Step 44: 17415 + 405 = 17820
Step 45: 17820 + 405 = 18225
Step 46: 18225 + 405 = 18630
Step 47: 18630 + 405 = 19035
Step 48: 19035 + 405 = 19440
Step 49: 19440 + 405 = 19845
Step 50: 19845 + 405 = 20250
Step 51: 20250 + 405 = 20655
Step 52: 20655 + 405 = 21060
Step 53: 21060 + 405 = 21465
Step 54: 21465 + 405 = 21870
Step 55: 21870 + 405 = 22275
Step 56: 22275 + 405 = 22680
Step 57: 22680 + 405 = 23085
Step 58: 23085 + 405 = 23490
Step 59: 23490 + 405 = 23895
Step 60: 23895 + 405 = 24300
Step 61: 24300 + 405 = 24705

So, 405*61 = 24705