Let's roll up our sleeves and solve this. We have 996 and we're going to multiply it by 13, essentially adding 996 to itself 13 times.
Step 1: 0 + 996 = 996
Step 2: 996 + 996 = 1992
Step 3: 1992 + 996 = 2988
Step 4: 2988 + 996 = 3984
Step 5: 3984 + 996 = 4980
Step 6: 4980 + 996 = 5976
Step 7: 5976 + 996 = 6972
Step 8: 6972 + 996 = 7968
Step 9: 7968 + 996 = 8964
Step 10: 8964 + 996 = 9960
Step 11: 9960 + 996 = 10956
Step 12: 10956 + 996 = 11952
Step 13: 11952 + 996 = 12948

So, 996*13 = 12948