Alright, let's solve this math problem step by step. First, we have the number 84. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 31. So, we're going to take the number 84 and add it to itself 31 times.
Step 1: 0 + 84 = 84
Step 2: 84 + 84 = 168
Step 3: 168 + 84 = 252
Step 4: 252 + 84 = 336
Step 5: 336 + 84 = 420
Step 6: 420 + 84 = 504
Step 7: 504 + 84 = 588
Step 8: 588 + 84 = 672
Step 9: 672 + 84 = 756
Step 10: 756 + 84 = 840
Step 11: 840 + 84 = 924
Step 12: 924 + 84 = 1008
Step 13: 1008 + 84 = 1092
Step 14: 1092 + 84 = 1176
Step 15: 1176 + 84 = 1260
Step 16: 1260 + 84 = 1344
Step 17: 1344 + 84 = 1428
Step 18: 1428 + 84 = 1512
Step 19: 1512 + 84 = 1596
Step 20: 1596 + 84 = 1680
Step 21: 1680 + 84 = 1764
Step 22: 1764 + 84 = 1848
Step 23: 1848 + 84 = 1932
Step 24: 1932 + 84 = 2016
Step 25: 2016 + 84 = 2100
Step 26: 2100 + 84 = 2184
Step 27: 2184 + 84 = 2268
Step 28: 2268 + 84 = 2352
Step 29: 2352 + 84 = 2436
Step 30: 2436 + 84 = 2520
Step 31: 2520 + 84 = 2604

So, 84*31 = 2604