Let's roll up our sleeves and solve this. We have 535 and we're going to multiply it by 15, essentially adding 535 to itself 15 times.
Step 1: 0 + 535 = 535
Step 2: 535 + 535 = 1070
Step 3: 1070 + 535 = 1605
Step 4: 1605 + 535 = 2140
Step 5: 2140 + 535 = 2675
Step 6: 2675 + 535 = 3210
Step 7: 3210 + 535 = 3745
Step 8: 3745 + 535 = 4280
Step 9: 4280 + 535 = 4815
Step 10: 4815 + 535 = 5350
Step 11: 5350 + 535 = 5885
Step 12: 5885 + 535 = 6420
Step 13: 6420 + 535 = 6955
Step 14: 6955 + 535 = 7490
Step 15: 7490 + 535 = 8025

So, 535*15 = 8025