Let's roll up our sleeves and solve this. We have 402 and we're going to multiply it by 15, essentially adding 402 to itself 15 times.
Step 1: 0 + 402 = 402
Step 2: 402 + 402 = 804
Step 3: 804 + 402 = 1206
Step 4: 1206 + 402 = 1608
Step 5: 1608 + 402 = 2010
Step 6: 2010 + 402 = 2412
Step 7: 2412 + 402 = 2814
Step 8: 2814 + 402 = 3216
Step 9: 3216 + 402 = 3618
Step 10: 3618 + 402 = 4020
Step 11: 4020 + 402 = 4422
Step 12: 4422 + 402 = 4824
Step 13: 4824 + 402 = 5226
Step 14: 5226 + 402 = 5628
Step 15: 5628 + 402 = 6030

So, 402*15 = 6030