Sure thing, let's get straight to it. We start with 841 and we're going to multiply it by 25, which means adding 841 to itself 25 times.
Step 1: 0 + 841 = 841
Step 2: 841 + 841 = 1682
Step 3: 1682 + 841 = 2523
Step 4: 2523 + 841 = 3364
Step 5: 3364 + 841 = 4205
Step 6: 4205 + 841 = 5046
Step 7: 5046 + 841 = 5887
Step 8: 5887 + 841 = 6728
Step 9: 6728 + 841 = 7569
Step 10: 7569 + 841 = 8410
Step 11: 8410 + 841 = 9251
Step 12: 9251 + 841 = 10092
Step 13: 10092 + 841 = 10933
Step 14: 10933 + 841 = 11774
Step 15: 11774 + 841 = 12615
Step 16: 12615 + 841 = 13456
Step 17: 13456 + 841 = 14297
Step 18: 14297 + 841 = 15138
Step 19: 15138 + 841 = 15979
Step 20: 15979 + 841 = 16820
Step 21: 16820 + 841 = 17661
Step 22: 17661 + 841 = 18502
Step 23: 18502 + 841 = 19343
Step 24: 19343 + 841 = 20184
Step 25: 20184 + 841 = 21025

So, 841*25 = 21025