OK, let's work through this together. We're starting with 171 and we're going to multiply it by 25, which means we add 171 to itself 25 times.
Step 1: 0 + 171 = 171
Step 2: 171 + 171 = 342
Step 3: 342 + 171 = 513
Step 4: 513 + 171 = 684
Step 5: 684 + 171 = 855
Step 6: 855 + 171 = 1026
Step 7: 1026 + 171 = 1197
Step 8: 1197 + 171 = 1368
Step 9: 1368 + 171 = 1539
Step 10: 1539 + 171 = 1710
Step 11: 1710 + 171 = 1881
Step 12: 1881 + 171 = 2052
Step 13: 2052 + 171 = 2223
Step 14: 2223 + 171 = 2394
Step 15: 2394 + 171 = 2565
Step 16: 2565 + 171 = 2736
Step 17: 2736 + 171 = 2907
Step 18: 2907 + 171 = 3078
Step 19: 3078 + 171 = 3249
Step 20: 3249 + 171 = 3420
Step 21: 3420 + 171 = 3591
Step 22: 3591 + 171 = 3762
Step 23: 3762 + 171 = 3933
Step 24: 3933 + 171 = 4104
Step 25: 4104 + 171 = 4275

So, 171*25 = 4275