OK, let's crack this. We're given 155 and our task is to multiply it by 13. Essentially, we'll be adding 155 to itself 13 times.
Step 1: 0 + 155 = 155
Step 2: 155 + 155 = 310
Step 3: 310 + 155 = 465
Step 4: 465 + 155 = 620
Step 5: 620 + 155 = 775
Step 6: 775 + 155 = 930
Step 7: 930 + 155 = 1085
Step 8: 1085 + 155 = 1240
Step 9: 1240 + 155 = 1395
Step 10: 1395 + 155 = 1550
Step 11: 1550 + 155 = 1705
Step 12: 1705 + 155 = 1860
Step 13: 1860 + 155 = 2015

So, 155*13 = 2015