Let's get this math done. We have 915 and we're going to multiply it by 9. This is the same as taking 915 and adding it to itself 9 times.
Step 1: 0 + 915 = 915
Step 2: 915 + 915 = 1830
Step 3: 1830 + 915 = 2745
Step 4: 2745 + 915 = 3660
Step 5: 3660 + 915 = 4575
Step 6: 4575 + 915 = 5490
Step 7: 5490 + 915 = 6405
Step 8: 6405 + 915 = 7320
Step 9: 7320 + 915 = 8235

So, 915*9 = 8235