OK, let's work through this together. We're starting with 519 and we're going to multiply it by 39, which means we add 519 to itself 39 times.
Step 1: 0 + 519 = 519
Step 2: 519 + 519 = 1038
Step 3: 1038 + 519 = 1557
Step 4: 1557 + 519 = 2076
Step 5: 2076 + 519 = 2595
Step 6: 2595 + 519 = 3114
Step 7: 3114 + 519 = 3633
Step 8: 3633 + 519 = 4152
Step 9: 4152 + 519 = 4671
Step 10: 4671 + 519 = 5190
Step 11: 5190 + 519 = 5709
Step 12: 5709 + 519 = 6228
Step 13: 6228 + 519 = 6747
Step 14: 6747 + 519 = 7266
Step 15: 7266 + 519 = 7785
Step 16: 7785 + 519 = 8304
Step 17: 8304 + 519 = 8823
Step 18: 8823 + 519 = 9342
Step 19: 9342 + 519 = 9861
Step 20: 9861 + 519 = 10380
Step 21: 10380 + 519 = 10899
Step 22: 10899 + 519 = 11418
Step 23: 11418 + 519 = 11937
Step 24: 11937 + 519 = 12456
Step 25: 12456 + 519 = 12975
Step 26: 12975 + 519 = 13494
Step 27: 13494 + 519 = 14013
Step 28: 14013 + 519 = 14532
Step 29: 14532 + 519 = 15051
Step 30: 15051 + 519 = 15570
Step 31: 15570 + 519 = 16089
Step 32: 16089 + 519 = 16608
Step 33: 16608 + 519 = 17127
Step 34: 17127 + 519 = 17646
Step 35: 17646 + 519 = 18165
Step 36: 18165 + 519 = 18684
Step 37: 18684 + 519 = 19203
Step 38: 19203 + 519 = 19722
Step 39: 19722 + 519 = 20241

So, 519*39 = 20241