How many three-letter codes can be made from 7 letters FGHIJKL if repetition of letters?

If repetition of letters is allowed, each position in the three-letter code can be filled by any of the 7 letters (F, G, H, I, J, K, L). Therefore, for each of the three positions in the code, there are 7 choices. The total number of three-letter codes can be calculated as (7 \times 7 \times 7 = 7^3 = 343). Thus, 343 different three-letter codes can be formed.