OK, let's work through this together. We're starting with 624 and we're going to multiply it by 5, which means we add 624 to itself 5 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

So, 624*5 = 3120