OK, let's crack this. We're given 605 and our task is to multiply it by 45. Essentially, we'll be adding 605 to itself 45 times.
Step 1: 0 + 605 = 605
Step 2: 605 + 605 = 1210
Step 3: 1210 + 605 = 1815
Step 4: 1815 + 605 = 2420
Step 5: 2420 + 605 = 3025
Step 6: 3025 + 605 = 3630
Step 7: 3630 + 605 = 4235
Step 8: 4235 + 605 = 4840
Step 9: 4840 + 605 = 5445
Step 10: 5445 + 605 = 6050
Step 11: 6050 + 605 = 6655
Step 12: 6655 + 605 = 7260
Step 13: 7260 + 605 = 7865
Step 14: 7865 + 605 = 8470
Step 15: 8470 + 605 = 9075
Step 16: 9075 + 605 = 9680
Step 17: 9680 + 605 = 10285
Step 18: 10285 + 605 = 10890
Step 19: 10890 + 605 = 11495
Step 20: 11495 + 605 = 12100
Step 21: 12100 + 605 = 12705
Step 22: 12705 + 605 = 13310
Step 23: 13310 + 605 = 13915
Step 24: 13915 + 605 = 14520
Step 25: 14520 + 605 = 15125
Step 26: 15125 + 605 = 15730
Step 27: 15730 + 605 = 16335
Step 28: 16335 + 605 = 16940
Step 29: 16940 + 605 = 17545
Step 30: 17545 + 605 = 18150
Step 31: 18150 + 605 = 18755
Step 32: 18755 + 605 = 19360
Step 33: 19360 + 605 = 19965
Step 34: 19965 + 605 = 20570
Step 35: 20570 + 605 = 21175
Step 36: 21175 + 605 = 21780
Step 37: 21780 + 605 = 22385
Step 38: 22385 + 605 = 22990
Step 39: 22990 + 605 = 23595
Step 40: 23595 + 605 = 24200
Step 41: 24200 + 605 = 24805
Step 42: 24805 + 605 = 25410
Step 43: 25410 + 605 = 26015
Step 44: 26015 + 605 = 26620
Step 45: 26620 + 605 = 27225

So, 605*45 = 27225