OK, let's crack this. We're given 297 and our task is to multiply it by 15. Essentially, we'll be adding 297 to itself 15 times.
Step 1: 0 + 297 = 297
Step 2: 297 + 297 = 594
Step 3: 594 + 297 = 891
Step 4: 891 + 297 = 1188
Step 5: 1188 + 297 = 1485
Step 6: 1485 + 297 = 1782
Step 7: 1782 + 297 = 2079
Step 8: 2079 + 297 = 2376
Step 9: 2376 + 297 = 2673
Step 10: 2673 + 297 = 2970
Step 11: 2970 + 297 = 3267
Step 12: 3267 + 297 = 3564
Step 13: 3564 + 297 = 3861
Step 14: 3861 + 297 = 4158
Step 15: 4158 + 297 = 4455

So, 297*15 = 4455