OK, let's work through this together. We're starting with 385 and we're going to multiply it by 15, which means we add 385 to itself 15 times.
Step 1: 0 + 385 = 385
Step 2: 385 + 385 = 770
Step 3: 770 + 385 = 1155
Step 4: 1155 + 385 = 1540
Step 5: 1540 + 385 = 1925
Step 6: 1925 + 385 = 2310
Step 7: 2310 + 385 = 2695
Step 8: 2695 + 385 = 3080
Step 9: 3080 + 385 = 3465
Step 10: 3465 + 385 = 3850
Step 11: 3850 + 385 = 4235
Step 12: 4235 + 385 = 4620
Step 13: 4620 + 385 = 5005
Step 14: 5005 + 385 = 5390
Step 15: 5390 + 385 = 5775

So, 385*15 = 5775