OK, let's crack this. We're given 630 and our task is to multiply it by 3. Essentially, we'll be adding 630 to itself 3 times.
Step 1: 0 + 630 = 630
Step 2: 630 + 630 = 1260
Step 3: 1260 + 630 = 1890

So, 630*3 = 1890