OK, let's work through this together. We're starting with 833 and we're going to multiply it by 31, which means we add 833 to itself 31 times.
Step 1: 0 + 833 = 833
Step 2: 833 + 833 = 1666
Step 3: 1666 + 833 = 2499
Step 4: 2499 + 833 = 3332
Step 5: 3332 + 833 = 4165
Step 6: 4165 + 833 = 4998
Step 7: 4998 + 833 = 5831
Step 8: 5831 + 833 = 6664
Step 9: 6664 + 833 = 7497
Step 10: 7497 + 833 = 8330
Step 11: 8330 + 833 = 9163
Step 12: 9163 + 833 = 9996
Step 13: 9996 + 833 = 10829
Step 14: 10829 + 833 = 11662
Step 15: 11662 + 833 = 12495
Step 16: 12495 + 833 = 13328
Step 17: 13328 + 833 = 14161
Step 18: 14161 + 833 = 14994
Step 19: 14994 + 833 = 15827
Step 20: 15827 + 833 = 16660
Step 21: 16660 + 833 = 17493
Step 22: 17493 + 833 = 18326
Step 23: 18326 + 833 = 19159
Step 24: 19159 + 833 = 19992
Step 25: 19992 + 833 = 20825
Step 26: 20825 + 833 = 21658
Step 27: 21658 + 833 = 22491
Step 28: 22491 + 833 = 23324
Step 29: 23324 + 833 = 24157
Step 30: 24157 + 833 = 24990
Step 31: 24990 + 833 = 25823

So, 833*31 = 25823