Let's roll up our sleeves and solve this. We have 39 and we're going to multiply it by 48, essentially adding 39 to itself 48 times.
Step 1: 0 + 39 = 39
Step 2: 39 + 39 = 78
Step 3: 78 + 39 = 117
Step 4: 117 + 39 = 156
Step 5: 156 + 39 = 195
Step 6: 195 + 39 = 234
Step 7: 234 + 39 = 273
Step 8: 273 + 39 = 312
Step 9: 312 + 39 = 351
Step 10: 351 + 39 = 390
Step 11: 390 + 39 = 429
Step 12: 429 + 39 = 468
Step 13: 468 + 39 = 507
Step 14: 507 + 39 = 546
Step 15: 546 + 39 = 585
Step 16: 585 + 39 = 624
Step 17: 624 + 39 = 663
Step 18: 663 + 39 = 702
Step 19: 702 + 39 = 741
Step 20: 741 + 39 = 780
Step 21: 780 + 39 = 819
Step 22: 819 + 39 = 858
Step 23: 858 + 39 = 897
Step 24: 897 + 39 = 936
Step 25: 936 + 39 = 975
Step 26: 975 + 39 = 1014
Step 27: 1014 + 39 = 1053
Step 28: 1053 + 39 = 1092
Step 29: 1092 + 39 = 1131
Step 30: 1131 + 39 = 1170
Step 31: 1170 + 39 = 1209
Step 32: 1209 + 39 = 1248
Step 33: 1248 + 39 = 1287
Step 34: 1287 + 39 = 1326
Step 35: 1326 + 39 = 1365
Step 36: 1365 + 39 = 1404
Step 37: 1404 + 39 = 1443
Step 38: 1443 + 39 = 1482
Step 39: 1482 + 39 = 1521
Step 40: 1521 + 39 = 1560
Step 41: 1560 + 39 = 1599
Step 42: 1599 + 39 = 1638
Step 43: 1638 + 39 = 1677
Step 44: 1677 + 39 = 1716
Step 45: 1716 + 39 = 1755
Step 46: 1755 + 39 = 1794
Step 47: 1794 + 39 = 1833
Step 48: 1833 + 39 = 1872

So, 39*48 = 1872