Let's get this math done. We have 606 and we're going to multiply it by 15. This is the same as taking 606 and adding it to itself 15 times.
Step 1: 0 + 606 = 606
Step 2: 606 + 606 = 1212
Step 3: 1212 + 606 = 1818
Step 4: 1818 + 606 = 2424
Step 5: 2424 + 606 = 3030
Step 6: 3030 + 606 = 3636
Step 7: 3636 + 606 = 4242
Step 8: 4242 + 606 = 4848
Step 9: 4848 + 606 = 5454
Step 10: 5454 + 606 = 6060
Step 11: 6060 + 606 = 6666
Step 12: 6666 + 606 = 7272
Step 13: 7272 + 606 = 7878
Step 14: 7878 + 606 = 8484
Step 15: 8484 + 606 = 9090

So, 606*15 = 9090