Without delay, let's solve this. We've got 921 and we will be multiplying it by 7, that is, adding 921 to itself 7 times.
Step 1: 0 + 921 = 921
Step 2: 921 + 921 = 1842
Step 3: 1842 + 921 = 2763
Step 4: 2763 + 921 = 3684
Step 5: 3684 + 921 = 4605
Step 6: 4605 + 921 = 5526
Step 7: 5526 + 921 = 6447

So, 921*7 = 6447