OK, let's crack this. We're given 379 and our task is to multiply it by 15. Essentially, we'll be adding 379 to itself 15 times.
Step 1: 0 + 379 = 379
Step 2: 379 + 379 = 758
Step 3: 758 + 379 = 1137
Step 4: 1137 + 379 = 1516
Step 5: 1516 + 379 = 1895
Step 6: 1895 + 379 = 2274
Step 7: 2274 + 379 = 2653
Step 8: 2653 + 379 = 3032
Step 9: 3032 + 379 = 3411
Step 10: 3411 + 379 = 3790
Step 11: 3790 + 379 = 4169
Step 12: 4169 + 379 = 4548
Step 13: 4548 + 379 = 4927
Step 14: 4927 + 379 = 5306
Step 15: 5306 + 379 = 5685

So, 379*15 = 5685