OK, let's work through this together. We're starting with 658 and we're going to multiply it by 25, which means we add 658 to itself 25 times.
Step 1: 0 + 658 = 658
Step 2: 658 + 658 = 1316
Step 3: 1316 + 658 = 1974
Step 4: 1974 + 658 = 2632
Step 5: 2632 + 658 = 3290
Step 6: 3290 + 658 = 3948
Step 7: 3948 + 658 = 4606
Step 8: 4606 + 658 = 5264
Step 9: 5264 + 658 = 5922
Step 10: 5922 + 658 = 6580
Step 11: 6580 + 658 = 7238
Step 12: 7238 + 658 = 7896
Step 13: 7896 + 658 = 8554
Step 14: 8554 + 658 = 9212
Step 15: 9212 + 658 = 9870
Step 16: 9870 + 658 = 10528
Step 17: 10528 + 658 = 11186
Step 18: 11186 + 658 = 11844
Step 19: 11844 + 658 = 12502
Step 20: 12502 + 658 = 13160
Step 21: 13160 + 658 = 13818
Step 22: 13818 + 658 = 14476
Step 23: 14476 + 658 = 15134
Step 24: 15134 + 658 = 15792
Step 25: 15792 + 658 = 16450

So, 658*25 = 16450