Let's roll up our sleeves and solve this. We have 86 and we're going to multiply it by 25, essentially adding 86 to itself 25 times.
Step 1: 0 + 86 = 86
Step 2: 86 + 86 = 172
Step 3: 172 + 86 = 258
Step 4: 258 + 86 = 344
Step 5: 344 + 86 = 430
Step 6: 430 + 86 = 516
Step 7: 516 + 86 = 602
Step 8: 602 + 86 = 688
Step 9: 688 + 86 = 774
Step 10: 774 + 86 = 860
Step 11: 860 + 86 = 946
Step 12: 946 + 86 = 1032
Step 13: 1032 + 86 = 1118
Step 14: 1118 + 86 = 1204
Step 15: 1204 + 86 = 1290
Step 16: 1290 + 86 = 1376
Step 17: 1376 + 86 = 1462
Step 18: 1462 + 86 = 1548
Step 19: 1548 + 86 = 1634
Step 20: 1634 + 86 = 1720
Step 21: 1720 + 86 = 1806
Step 22: 1806 + 86 = 1892
Step 23: 1892 + 86 = 1978
Step 24: 1978 + 86 = 2064
Step 25: 2064 + 86 = 2150

So, 86*25 = 2150