OK, let's work through this together. We're starting with 45 and we're going to multiply it by 23, which means we add 45 to itself 23 times.
Step 1: 0 + 45 = 45
Step 2: 45 + 45 = 90
Step 3: 90 + 45 = 135
Step 4: 135 + 45 = 180
Step 5: 180 + 45 = 225
Step 6: 225 + 45 = 270
Step 7: 270 + 45 = 315
Step 8: 315 + 45 = 360
Step 9: 360 + 45 = 405
Step 10: 405 + 45 = 450
Step 11: 450 + 45 = 495
Step 12: 495 + 45 = 540
Step 13: 540 + 45 = 585
Step 14: 585 + 45 = 630
Step 15: 630 + 45 = 675
Step 16: 675 + 45 = 720
Step 17: 720 + 45 = 765
Step 18: 765 + 45 = 810
Step 19: 810 + 45 = 855
Step 20: 855 + 45 = 900
Step 21: 900 + 45 = 945
Step 22: 945 + 45 = 990
Step 23: 990 + 45 = 1035

So, 45*23 = 1035