Let's get this math done. We have 84 and we're going to multiply it by 7. This is the same as taking 84 and adding it to itself 7 times.
Step 1: 0 + 84 = 84
Step 2: 84 + 84 = 168
Step 3: 168 + 84 = 252
Step 4: 252 + 84 = 336
Step 5: 336 + 84 = 420
Step 6: 420 + 84 = 504
Step 7: 504 + 84 = 588

So, 84*7 = 588