OK, let's crack this. We're given 721 and our task is to multiply it by 5. Essentially, we'll be adding 721 to itself 5 times.
Step 1: 0 + 721 = 721
Step 2: 721 + 721 = 1442
Step 3: 1442 + 721 = 2163
Step 4: 2163 + 721 = 2884
Step 5: 2884 + 721 = 3605

So, 721*5 = 3605