OK, let's crack this. We're given 676 and our task is to multiply it by 15. Essentially, we'll be adding 676 to itself 15 times.
Step 1: 0 + 676 = 676
Step 2: 676 + 676 = 1352
Step 3: 1352 + 676 = 2028
Step 4: 2028 + 676 = 2704
Step 5: 2704 + 676 = 3380
Step 6: 3380 + 676 = 4056
Step 7: 4056 + 676 = 4732
Step 8: 4732 + 676 = 5408
Step 9: 5408 + 676 = 6084
Step 10: 6084 + 676 = 6760
Step 11: 6760 + 676 = 7436
Step 12: 7436 + 676 = 8112
Step 13: 8112 + 676 = 8788
Step 14: 8788 + 676 = 9464
Step 15: 9464 + 676 = 10140

So, 676*15 = 10140