# How can I calculate the silent mutation for each position in codon?

I am trying to find the number of silent mutations in for each position in codon.

In the homework, I am asked:

For the codons and for each position, count the number of silent mutation. There are 64 codons, for each position there are 3 mutations leading to a change at the DNA level. There are thus 192 possible mutations for each of the three positions of the codons. For each position, print the number of silent mutations.

I understand stand silent mutation is the mutation that doesn't lead to amino acid change. For example, GCC can become GCT but it is still Thr

I am not sure what does "calculating silent mutation for each position" mean? I mean it is easy to find silent mutation for each codon like the example I gave above, but couldn't really understand how to calculate the silent mutation for each position.

Should I change letters (nucleotides) one by one and see if it causing a silent mutation?

Calculate in this context would just mean determine. You don't actually have to change every base to determine whether a change is silent. Instead, try building a hash table of amino acids to codons, which you can then quickly iterate over to find all silent changes.