OK, let's work through this together. We're starting with 121 and we're going to multiply it by 36, which means we add 121 to itself 36 times.
Step 1: 0 + 121 = 121
Step 2: 121 + 121 = 242
Step 3: 242 + 121 = 363
Step 4: 363 + 121 = 484
Step 5: 484 + 121 = 605
Step 6: 605 + 121 = 726
Step 7: 726 + 121 = 847
Step 8: 847 + 121 = 968
Step 9: 968 + 121 = 1089
Step 10: 1089 + 121 = 1210
Step 11: 1210 + 121 = 1331
Step 12: 1331 + 121 = 1452
Step 13: 1452 + 121 = 1573
Step 14: 1573 + 121 = 1694
Step 15: 1694 + 121 = 1815
Step 16: 1815 + 121 = 1936
Step 17: 1936 + 121 = 2057
Step 18: 2057 + 121 = 2178
Step 19: 2178 + 121 = 2299
Step 20: 2299 + 121 = 2420
Step 21: 2420 + 121 = 2541
Step 22: 2541 + 121 = 2662
Step 23: 2662 + 121 = 2783
Step 24: 2783 + 121 = 2904
Step 25: 2904 + 121 = 3025
Step 26: 3025 + 121 = 3146
Step 27: 3146 + 121 = 3267
Step 28: 3267 + 121 = 3388
Step 29: 3388 + 121 = 3509
Step 30: 3509 + 121 = 3630
Step 31: 3630 + 121 = 3751
Step 32: 3751 + 121 = 3872
Step 33: 3872 + 121 = 3993
Step 34: 3993 + 121 = 4114
Step 35: 4114 + 121 = 4235
Step 36: 4235 + 121 = 4356

So, 121*36 = 4356