OK, let's work through this together. We're starting with 354 and we're going to multiply it by 50, which means we add 354 to itself 50 times.
Step 1: 0 + 354 = 354
Step 2: 354 + 354 = 708
Step 3: 708 + 354 = 1062
Step 4: 1062 + 354 = 1416
Step 5: 1416 + 354 = 1770
Step 6: 1770 + 354 = 2124
Step 7: 2124 + 354 = 2478
Step 8: 2478 + 354 = 2832
Step 9: 2832 + 354 = 3186
Step 10: 3186 + 354 = 3540
Step 11: 3540 + 354 = 3894
Step 12: 3894 + 354 = 4248
Step 13: 4248 + 354 = 4602
Step 14: 4602 + 354 = 4956
Step 15: 4956 + 354 = 5310
Step 16: 5310 + 354 = 5664
Step 17: 5664 + 354 = 6018
Step 18: 6018 + 354 = 6372
Step 19: 6372 + 354 = 6726
Step 20: 6726 + 354 = 7080
Step 21: 7080 + 354 = 7434
Step 22: 7434 + 354 = 7788
Step 23: 7788 + 354 = 8142
Step 24: 8142 + 354 = 8496
Step 25: 8496 + 354 = 8850
Step 26: 8850 + 354 = 9204
Step 27: 9204 + 354 = 9558
Step 28: 9558 + 354 = 9912
Step 29: 9912 + 354 = 10266
Step 30: 10266 + 354 = 10620
Step 31: 10620 + 354 = 10974
Step 32: 10974 + 354 = 11328
Step 33: 11328 + 354 = 11682
Step 34: 11682 + 354 = 12036
Step 35: 12036 + 354 = 12390
Step 36: 12390 + 354 = 12744
Step 37: 12744 + 354 = 13098
Step 38: 13098 + 354 = 13452
Step 39: 13452 + 354 = 13806
Step 40: 13806 + 354 = 14160
Step 41: 14160 + 354 = 14514
Step 42: 14514 + 354 = 14868
Step 43: 14868 + 354 = 15222
Step 44: 15222 + 354 = 15576
Step 45: 15576 + 354 = 15930
Step 46: 15930 + 354 = 16284
Step 47: 16284 + 354 = 16638
Step 48: 16638 + 354 = 16992
Step 49: 16992 + 354 = 17346
Step 50: 17346 + 354 = 17700

So, 354*50 = 17700