OK, let's work through this together. We're starting with 321 and we're going to multiply it by 88, which means we add 321 to itself 88 times.
Step 1: 0 + 321 = 321
Step 2: 321 + 321 = 642
Step 3: 642 + 321 = 963
Step 4: 963 + 321 = 1284
Step 5: 1284 + 321 = 1605
Step 6: 1605 + 321 = 1926
Step 7: 1926 + 321 = 2247
Step 8: 2247 + 321 = 2568
Step 9: 2568 + 321 = 2889
Step 10: 2889 + 321 = 3210
Step 11: 3210 + 321 = 3531
Step 12: 3531 + 321 = 3852
Step 13: 3852 + 321 = 4173
Step 14: 4173 + 321 = 4494
Step 15: 4494 + 321 = 4815
Step 16: 4815 + 321 = 5136
Step 17: 5136 + 321 = 5457
Step 18: 5457 + 321 = 5778
Step 19: 5778 + 321 = 6099
Step 20: 6099 + 321 = 6420
Step 21: 6420 + 321 = 6741
Step 22: 6741 + 321 = 7062
Step 23: 7062 + 321 = 7383
Step 24: 7383 + 321 = 7704
Step 25: 7704 + 321 = 8025
Step 26: 8025 + 321 = 8346
Step 27: 8346 + 321 = 8667
Step 28: 8667 + 321 = 8988
Step 29: 8988 + 321 = 9309
Step 30: 9309 + 321 = 9630
Step 31: 9630 + 321 = 9951
Step 32: 9951 + 321 = 10272
Step 33: 10272 + 321 = 10593
Step 34: 10593 + 321 = 10914
Step 35: 10914 + 321 = 11235
Step 36: 11235 + 321 = 11556
Step 37: 11556 + 321 = 11877
Step 38: 11877 + 321 = 12198
Step 39: 12198 + 321 = 12519
Step 40: 12519 + 321 = 12840
Step 41: 12840 + 321 = 13161
Step 42: 13161 + 321 = 13482
Step 43: 13482 + 321 = 13803
Step 44: 13803 + 321 = 14124
Step 45: 14124 + 321 = 14445
Step 46: 14445 + 321 = 14766
Step 47: 14766 + 321 = 15087
Step 48: 15087 + 321 = 15408
Step 49: 15408 + 321 = 15729
Step 50: 15729 + 321 = 16050
Step 51: 16050 + 321 = 16371
Step 52: 16371 + 321 = 16692
Step 53: 16692 + 321 = 17013
Step 54: 17013 + 321 = 17334
Step 55: 17334 + 321 = 17655
Step 56: 17655 + 321 = 17976
Step 57: 17976 + 321 = 18297
Step 58: 18297 + 321 = 18618
Step 59: 18618 + 321 = 18939
Step 60: 18939 + 321 = 19260
Step 61: 19260 + 321 = 19581
Step 62: 19581 + 321 = 19902
Step 63: 19902 + 321 = 20223
Step 64: 20223 + 321 = 20544
Step 65: 20544 + 321 = 20865
Step 66: 20865 + 321 = 21186
Step 67: 21186 + 321 = 21507
Step 68: 21507 + 321 = 21828
Step 69: 21828 + 321 = 22149
Step 70: 22149 + 321 = 22470
Step 71: 22470 + 321 = 22791
Step 72: 22791 + 321 = 23112
Step 73: 23112 + 321 = 23433
Step 74: 23433 + 321 = 23754
Step 75: 23754 + 321 = 24075
Step 76: 24075 + 321 = 24396
Step 77: 24396 + 321 = 24717
Step 78: 24717 + 321 = 25038
Step 79: 25038 + 321 = 25359
Step 80: 25359 + 321 = 25680
Step 81: 25680 + 321 = 26001
Step 82: 26001 + 321 = 26322
Step 83: 26322 + 321 = 26643
Step 84: 26643 + 321 = 26964
Step 85: 26964 + 321 = 27285
Step 86: 27285 + 321 = 27606
Step 87: 27606 + 321 = 27927
Step 88: 27927 + 321 = 28248

So, 321*88 = 28248