Let's get this math done. We have 121 and we're going to multiply it by 7. This is the same as taking 121 and adding it to itself 7 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

So, 121*7 = 847