OK, let's work through this together. We're starting with 313 and we're going to multiply it by 15, which means we add 313 to itself 15 times.
Step 1: 0 + 313 = 313
Step 2: 313 + 313 = 626
Step 3: 626 + 313 = 939
Step 4: 939 + 313 = 1252
Step 5: 1252 + 313 = 1565
Step 6: 1565 + 313 = 1878
Step 7: 1878 + 313 = 2191
Step 8: 2191 + 313 = 2504
Step 9: 2504 + 313 = 2817
Step 10: 2817 + 313 = 3130
Step 11: 3130 + 313 = 3443
Step 12: 3443 + 313 = 3756
Step 13: 3756 + 313 = 4069
Step 14: 4069 + 313 = 4382
Step 15: 4382 + 313 = 4695

So, 313*15 = 4695