OK, let's crack this. We're given 624 and our task is to multiply it by 7. Essentially, we'll be adding 624 to itself 7 times.
Step 1: 0 + 624 = 624
Step 2: 624 + 624 = 1248
Step 3: 1248 + 624 = 1872
Step 4: 1872 + 624 = 2496
Step 5: 2496 + 624 = 3120
Step 6: 3120 + 624 = 3744
Step 7: 3744 + 624 = 4368

So, 624*7 = 4368