Let's get this math done. We have 123 and we're going to multiply it by 16. This is the same as taking 123 and adding it to itself 16 times.
Step 1: 0 + 123 = 123
Step 2: 123 + 123 = 246
Step 3: 246 + 123 = 369
Step 4: 369 + 123 = 492
Step 5: 492 + 123 = 615
Step 6: 615 + 123 = 738
Step 7: 738 + 123 = 861
Step 8: 861 + 123 = 984
Step 9: 984 + 123 = 1107
Step 10: 1107 + 123 = 1230
Step 11: 1230 + 123 = 1353
Step 12: 1353 + 123 = 1476
Step 13: 1476 + 123 = 1599
Step 14: 1599 + 123 = 1722
Step 15: 1722 + 123 = 1845
Step 16: 1845 + 123 = 1968

So, 123*16 = 1968