Let's roll up our sleeves and solve this. We have 209 and we're going to multiply it by 20, essentially adding 209 to itself 20 times.
Step 1: 0 + 209 = 209
Step 2: 209 + 209 = 418
Step 3: 418 + 209 = 627
Step 4: 627 + 209 = 836
Step 5: 836 + 209 = 1045
Step 6: 1045 + 209 = 1254
Step 7: 1254 + 209 = 1463
Step 8: 1463 + 209 = 1672
Step 9: 1672 + 209 = 1881
Step 10: 1881 + 209 = 2090
Step 11: 2090 + 209 = 2299
Step 12: 2299 + 209 = 2508
Step 13: 2508 + 209 = 2717
Step 14: 2717 + 209 = 2926
Step 15: 2926 + 209 = 3135
Step 16: 3135 + 209 = 3344
Step 17: 3344 + 209 = 3553
Step 18: 3553 + 209 = 3762
Step 19: 3762 + 209 = 3971
Step 20: 3971 + 209 = 4180

So, 209*20 = 4180