OK, let's crack this. We're given 121 and our task is to multiply it by 5. Essentially, we'll be adding 121 to itself 5 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

So, 121*5 = 605