Let's roll up our sleeves and solve this. We have 372 and we're going to multiply it by 57, essentially adding 372 to itself 57 times.
Step 1: 0 + 372 = 372
Step 2: 372 + 372 = 744
Step 3: 744 + 372 = 1116
Step 4: 1116 + 372 = 1488
Step 5: 1488 + 372 = 1860
Step 6: 1860 + 372 = 2232
Step 7: 2232 + 372 = 2604
Step 8: 2604 + 372 = 2976
Step 9: 2976 + 372 = 3348
Step 10: 3348 + 372 = 3720
Step 11: 3720 + 372 = 4092
Step 12: 4092 + 372 = 4464
Step 13: 4464 + 372 = 4836
Step 14: 4836 + 372 = 5208
Step 15: 5208 + 372 = 5580
Step 16: 5580 + 372 = 5952
Step 17: 5952 + 372 = 6324
Step 18: 6324 + 372 = 6696
Step 19: 6696 + 372 = 7068
Step 20: 7068 + 372 = 7440
Step 21: 7440 + 372 = 7812
Step 22: 7812 + 372 = 8184
Step 23: 8184 + 372 = 8556
Step 24: 8556 + 372 = 8928
Step 25: 8928 + 372 = 9300
Step 26: 9300 + 372 = 9672
Step 27: 9672 + 372 = 10044
Step 28: 10044 + 372 = 10416
Step 29: 10416 + 372 = 10788
Step 30: 10788 + 372 = 11160
Step 31: 11160 + 372 = 11532
Step 32: 11532 + 372 = 11904
Step 33: 11904 + 372 = 12276
Step 34: 12276 + 372 = 12648
Step 35: 12648 + 372 = 13020
Step 36: 13020 + 372 = 13392
Step 37: 13392 + 372 = 13764
Step 38: 13764 + 372 = 14136
Step 39: 14136 + 372 = 14508
Step 40: 14508 + 372 = 14880
Step 41: 14880 + 372 = 15252
Step 42: 15252 + 372 = 15624
Step 43: 15624 + 372 = 15996
Step 44: 15996 + 372 = 16368
Step 45: 16368 + 372 = 16740
Step 46: 16740 + 372 = 17112
Step 47: 17112 + 372 = 17484
Step 48: 17484 + 372 = 17856
Step 49: 17856 + 372 = 18228
Step 50: 18228 + 372 = 18600
Step 51: 18600 + 372 = 18972
Step 52: 18972 + 372 = 19344
Step 53: 19344 + 372 = 19716
Step 54: 19716 + 372 = 20088
Step 55: 20088 + 372 = 20460
Step 56: 20460 + 372 = 20832
Step 57: 20832 + 372 = 21204

So, 372*57 = 21204