Alright, let's solve this math problem step by step. First, we have the number 685. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 25. So, we're going to take the number 685 and add it to itself 25 times.
Step 1: 0 + 685 = 685
Step 2: 685 + 685 = 1370
Step 3: 1370 + 685 = 2055
Step 4: 2055 + 685 = 2740
Step 5: 2740 + 685 = 3425
Step 6: 3425 + 685 = 4110
Step 7: 4110 + 685 = 4795
Step 8: 4795 + 685 = 5480
Step 9: 5480 + 685 = 6165
Step 10: 6165 + 685 = 6850
Step 11: 6850 + 685 = 7535
Step 12: 7535 + 685 = 8220
Step 13: 8220 + 685 = 8905
Step 14: 8905 + 685 = 9590
Step 15: 9590 + 685 = 10275
Step 16: 10275 + 685 = 10960
Step 17: 10960 + 685 = 11645
Step 18: 11645 + 685 = 12330
Step 19: 12330 + 685 = 13015
Step 20: 13015 + 685 = 13700
Step 21: 13700 + 685 = 14385
Step 22: 14385 + 685 = 15070
Step 23: 15070 + 685 = 15755
Step 24: 15755 + 685 = 16440
Step 25: 16440 + 685 = 17125

So, 685*25 = 17125