OK, let's work through this together. We're starting with 273 and we're going to multiply it by 20, which means we add 273 to itself 20 times.
Step 1: 0 + 273 = 273
Step 2: 273 + 273 = 546
Step 3: 546 + 273 = 819
Step 4: 819 + 273 = 1092
Step 5: 1092 + 273 = 1365
Step 6: 1365 + 273 = 1638
Step 7: 1638 + 273 = 1911
Step 8: 1911 + 273 = 2184
Step 9: 2184 + 273 = 2457
Step 10: 2457 + 273 = 2730
Step 11: 2730 + 273 = 3003
Step 12: 3003 + 273 = 3276
Step 13: 3276 + 273 = 3549
Step 14: 3549 + 273 = 3822
Step 15: 3822 + 273 = 4095
Step 16: 4095 + 273 = 4368
Step 17: 4368 + 273 = 4641
Step 18: 4641 + 273 = 4914
Step 19: 4914 + 273 = 5187
Step 20: 5187 + 273 = 5460

So, 273*20 = 5460