Let's roll up our sleeves and solve this. We have 350 and we're going to multiply it by 13, essentially adding 350 to itself 13 times.
Step 1: 0 + 350 = 350
Step 2: 350 + 350 = 700
Step 3: 700 + 350 = 1050
Step 4: 1050 + 350 = 1400
Step 5: 1400 + 350 = 1750
Step 6: 1750 + 350 = 2100
Step 7: 2100 + 350 = 2450
Step 8: 2450 + 350 = 2800
Step 9: 2800 + 350 = 3150
Step 10: 3150 + 350 = 3500
Step 11: 3500 + 350 = 3850
Step 12: 3850 + 350 = 4200
Step 13: 4200 + 350 = 4550

So, 350*13 = 4550