Let's roll up our sleeves and solve this. We have 620 and we're going to multiply it by 9, essentially adding 620 to itself 9 times.
Step 1: 0 + 620 = 620
Step 2: 620 + 620 = 1240
Step 3: 1240 + 620 = 1860
Step 4: 1860 + 620 = 2480
Step 5: 2480 + 620 = 3100
Step 6: 3100 + 620 = 3720
Step 7: 3720 + 620 = 4340
Step 8: 4340 + 620 = 4960
Step 9: 4960 + 620 = 5580

So, 620*9 = 5580