Alright, let's solve this math problem step by step. First, we have the number 994. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 21. So, we're going to take the number 994 and add it to itself 21 times.
Step 1: 0 + 994 = 994
Step 2: 994 + 994 = 1988
Step 3: 1988 + 994 = 2982
Step 4: 2982 + 994 = 3976
Step 5: 3976 + 994 = 4970
Step 6: 4970 + 994 = 5964
Step 7: 5964 + 994 = 6958
Step 8: 6958 + 994 = 7952
Step 9: 7952 + 994 = 8946
Step 10: 8946 + 994 = 9940
Step 11: 9940 + 994 = 10934
Step 12: 10934 + 994 = 11928
Step 13: 11928 + 994 = 12922
Step 14: 12922 + 994 = 13916
Step 15: 13916 + 994 = 14910
Step 16: 14910 + 994 = 15904
Step 17: 15904 + 994 = 16898
Step 18: 16898 + 994 = 17892
Step 19: 17892 + 994 = 18886
Step 20: 18886 + 994 = 19880
Step 21: 19880 + 994 = 20874

So, 994*21 = 20874