OK, let's crack this. We're given 981 and our task is to multiply it by 126. Essentially, we'll be adding 981 to itself 126 times.
Step 1: 0 + 981 = 981
Step 2: 981 + 981 = 1962
Step 3: 1962 + 981 = 2943
Step 4: 2943 + 981 = 3924
Step 5: 3924 + 981 = 4905
Step 6: 4905 + 981 = 5886
Step 7: 5886 + 981 = 6867
Step 8: 6867 + 981 = 7848
Step 9: 7848 + 981 = 8829
Step 10: 8829 + 981 = 9810
Step 11: 9810 + 981 = 10791
Step 12: 10791 + 981 = 11772
Step 13: 11772 + 981 = 12753
Step 14: 12753 + 981 = 13734
Step 15: 13734 + 981 = 14715
Step 16: 14715 + 981 = 15696
Step 17: 15696 + 981 = 16677
Step 18: 16677 + 981 = 17658
Step 19: 17658 + 981 = 18639
Step 20: 18639 + 981 = 19620
Step 21: 19620 + 981 = 20601
Step 22: 20601 + 981 = 21582
Step 23: 21582 + 981 = 22563
Step 24: 22563 + 981 = 23544
Step 25: 23544 + 981 = 24525
Step 26: 24525 + 981 = 25506
Step 27: 25506 + 981 = 26487
Step 28: 26487 + 981 = 27468
Step 29: 27468 + 981 = 28449
Step 30: 28449 + 981 = 29430
Step 31: 29430 + 981 = 30411
Step 32: 30411 + 981 = 31392
Step 33: 31392 + 981 = 32373
Step 34: 32373 + 981 = 33354
Step 35: 33354 + 981 = 34335
Step 36: 34335 + 981 = 35316
Step 37: 35316 + 981 = 36297
Step 38: 36297 + 981 = 37278
Step 39: 37278 + 981 = 38259
Step 40: 38259 + 981 = 39240
Step 41: 39240 + 981 = 40221
Step 42: 40221 + 981 = 41202
Step 43: 41202 + 981 = 42183
Step 44: 42183 + 981 = 43164
Step 45: 43164 + 981 = 44145
Step 46: 44145 + 981 = 45126
Step 47: 45126 + 981 = 46107
Step 48: 46107 + 981 = 47088
Step 49: 47088 + 981 = 48069
Step 50: 48069 + 981 = 49050
Step 51: 49050 + 981 = 50031
Step 52: 50031 + 981 = 51012
Step 53: 51012 + 981 = 51993
Step 54: 51993 + 981 = 52974
Step 55: 52974 + 981 = 53955
Step 56: 53955 + 981 = 54936
Step 57: 54936 + 981 = 55917
Step 58: 55917 + 981 = 56898
Step 59: 56898 + 981 = 57879
Step 60: 57879 + 981 = 58860
Step 61: 58860 + 981 = 59841
Step 62: 59841 + 981 = 60822
Step 63: 60822 + 981 = 61803
Step 64: 61803 + 981 = 62784
Step 65: 62784 + 981 = 63765
Step 66: 63765 + 981 = 64746
Step 67: 64746 + 981 = 65727
Step 68: 65727 + 981 = 66708
Step 69: 66708 + 981 = 67689
Step 70: 67689 + 981 = 68670
Step 71: 68670 + 981 = 69651
Step 72: 69651 + 981 = 70632
Step 73: 70632 + 981 = 71613
Step 74: 71613 + 981 = 72594
Step 75: 72594 + 981 = 73575
Step 76: 73575 + 981 = 74556
Step 77: 74556 + 981 = 75537
Step 78: 75537 + 981 = 76518
Step 79: 76518 + 981 = 77499
Step 80: 77499 + 981 = 78480
Step 81: 78480 + 981 = 79461
Step 82: 79461 + 981 = 80442
Step 83: 80442 + 981 = 81423
Step 84: 81423 + 981 = 82404
Step 85: 82404 + 981 = 83385
Step 86: 83385 + 981 = 84366
Step 87: 84366 + 981 = 85347
Step 88: 85347 + 981 = 86328
Step 89: 86328 + 981 = 87309
Step 90: 87309 + 981 = 88290
Step 91: 88290 + 981 = 89271
Step 92: 89271 + 981 = 90252
Step 93: 90252 + 981 = 91233
Step 94: 91233 + 981 = 92214
Step 95: 92214 + 981 = 93195
Step 96: 93195 + 981 = 94176
Step 97: 94176 + 981 = 95157
Step 98: 95157 + 981 = 96138
Step 99: 96138 + 981 = 97119
Step 100: 97119 + 981 = 98100
Step 101: 98100 + 981 = 99081
Step 102: 99081 + 981 = 100062
Step 103: 100062 + 981 = 101043
Step 104: 101043 + 981 = 102024
Step 105: 102024 + 981 = 103005
Step 106: 103005 + 981 = 103986
Step 107: 103986 + 981 = 104967
Step 108: 104967 + 981 = 105948
Step 109: 105948 + 981 = 106929
Step 110: 106929 + 981 = 107910
Step 111: 107910 + 981 = 108891
Step 112: 108891 + 981 = 109872
Step 113: 109872 + 981 = 110853
Step 114: 110853 + 981 = 111834
Step 115: 111834 + 981 = 112815
Step 116: 112815 + 981 = 113796
Step 117: 113796 + 981 = 114777
Step 118: 114777 + 981 = 115758
Step 119: 115758 + 981 = 116739
Step 120: 116739 + 981 = 117720
Step 121: 117720 + 981 = 118701
Step 122: 118701 + 981 = 119682
Step 123: 119682 + 981 = 120663
Step 124: 120663 + 981 = 121644
Step 125: 121644 + 981 = 122625
Step 126: 122625 + 981 = 123606

So, 981*126 = 123606