Sure thing! We've got 378 and we're gonna multiply it by 54. That's the same as adding 378 to itself 54 times.
Step 1: 0 + 378 = 378
Step 2: 378 + 378 = 756
Step 3: 756 + 378 = 1134
Step 4: 1134 + 378 = 1512
Step 5: 1512 + 378 = 1890
Step 6: 1890 + 378 = 2268
Step 7: 2268 + 378 = 2646
Step 8: 2646 + 378 = 3024
Step 9: 3024 + 378 = 3402
Step 10: 3402 + 378 = 3780
Step 11: 3780 + 378 = 4158
Step 12: 4158 + 378 = 4536
Step 13: 4536 + 378 = 4914
Step 14: 4914 + 378 = 5292
Step 15: 5292 + 378 = 5670
Step 16: 5670 + 378 = 6048
Step 17: 6048 + 378 = 6426
Step 18: 6426 + 378 = 6804
Step 19: 6804 + 378 = 7182
Step 20: 7182 + 378 = 7560
Step 21: 7560 + 378 = 7938
Step 22: 7938 + 378 = 8316
Step 23: 8316 + 378 = 8694
Step 24: 8694 + 378 = 9072
Step 25: 9072 + 378 = 9450
Step 26: 9450 + 378 = 9828
Step 27: 9828 + 378 = 10206
Step 28: 10206 + 378 = 10584
Step 29: 10584 + 378 = 10962
Step 30: 10962 + 378 = 11340
Step 31: 11340 + 378 = 11718
Step 32: 11718 + 378 = 12096
Step 33: 12096 + 378 = 12474
Step 34: 12474 + 378 = 12852
Step 35: 12852 + 378 = 13230
Step 36: 13230 + 378 = 13608
Step 37: 13608 + 378 = 13986
Step 38: 13986 + 378 = 14364
Step 39: 14364 + 378 = 14742
Step 40: 14742 + 378 = 15120
Step 41: 15120 + 378 = 15498
Step 42: 15498 + 378 = 15876
Step 43: 15876 + 378 = 16254
Step 44: 16254 + 378 = 16632
Step 45: 16632 + 378 = 17010
Step 46: 17010 + 378 = 17388
Step 47: 17388 + 378 = 17766
Step 48: 17766 + 378 = 18144
Step 49: 18144 + 378 = 18522
Step 50: 18522 + 378 = 18900
Step 51: 18900 + 378 = 19278
Step 52: 19278 + 378 = 19656
Step 53: 19656 + 378 = 20034
Step 54: 20034 + 378 = 20412

So, 378*54 = 20412