OK, let's work through this together. We're starting with 403 and we're going to multiply it by 7, which means we add 403 to itself 7 times.
Step 1: 0 + 403 = 403
Step 2: 403 + 403 = 806
Step 3: 806 + 403 = 1209
Step 4: 1209 + 403 = 1612
Step 5: 1612 + 403 = 2015
Step 6: 2015 + 403 = 2418
Step 7: 2418 + 403 = 2821

So, 403*7 = 2821