OK, let's work through this together. We're starting with 355 and we're going to multiply it by 25, which means we add 355 to itself 25 times.
Step 1: 0 + 355 = 355
Step 2: 355 + 355 = 710
Step 3: 710 + 355 = 1065
Step 4: 1065 + 355 = 1420
Step 5: 1420 + 355 = 1775
Step 6: 1775 + 355 = 2130
Step 7: 2130 + 355 = 2485
Step 8: 2485 + 355 = 2840
Step 9: 2840 + 355 = 3195
Step 10: 3195 + 355 = 3550
Step 11: 3550 + 355 = 3905
Step 12: 3905 + 355 = 4260
Step 13: 4260 + 355 = 4615
Step 14: 4615 + 355 = 4970
Step 15: 4970 + 355 = 5325
Step 16: 5325 + 355 = 5680
Step 17: 5680 + 355 = 6035
Step 18: 6035 + 355 = 6390
Step 19: 6390 + 355 = 6745
Step 20: 6745 + 355 = 7100
Step 21: 7100 + 355 = 7455
Step 22: 7455 + 355 = 7810
Step 23: 7810 + 355 = 8165
Step 24: 8165 + 355 = 8520
Step 25: 8520 + 355 = 8875

So, 355*25 = 8875