Without delay, let's solve this. We've got 658 and we will be multiplying it by 15, that is, adding 658 to itself 15 times.
Step 1: 0 + 658 = 658
Step 2: 658 + 658 = 1316
Step 3: 1316 + 658 = 1974
Step 4: 1974 + 658 = 2632
Step 5: 2632 + 658 = 3290
Step 6: 3290 + 658 = 3948
Step 7: 3948 + 658 = 4606
Step 8: 4606 + 658 = 5264
Step 9: 5264 + 658 = 5922
Step 10: 5922 + 658 = 6580
Step 11: 6580 + 658 = 7238
Step 12: 7238 + 658 = 7896
Step 13: 7896 + 658 = 8554
Step 14: 8554 + 658 = 9212
Step 15: 9212 + 658 = 9870

So, 658*15 = 9870