Let's get this math done. We have 237 and we're going to multiply it by 13. This is the same as taking 237 and adding it to itself 13 times.
Step 1: 0 + 237 = 237
Step 2: 237 + 237 = 474
Step 3: 474 + 237 = 711
Step 4: 711 + 237 = 948
Step 5: 948 + 237 = 1185
Step 6: 1185 + 237 = 1422
Step 7: 1422 + 237 = 1659
Step 8: 1659 + 237 = 1896
Step 9: 1896 + 237 = 2133
Step 10: 2133 + 237 = 2370
Step 11: 2370 + 237 = 2607
Step 12: 2607 + 237 = 2844
Step 13: 2844 + 237 = 3081

So, 237*13 = 3081