Spelling with duplicate letters

Teaching Transcript

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How many ways can we spell the word 'heeded' with these letter tiles?

The interesting part is the duplicates, we have 3 letter tiles that are 'E's, and we have 2 letter tiles for the letter 'D'

Looking at the 'E' tiles, we have 3 options for the first tile, then for each of those, 2 for the second, and 1 for the third.

This is, in shorter form, 3 factorial

Then, looking at the 'D' tiles, we have 2 options for the first tile and then for each of those just 1 for the second.

Which is 2 factorial, if we write it in that notation

So our total number of ways of writing 'heeded' is 3 factorial, multiplied by 2 factorial

Which, when we work it out, is 12 ways to spell our word.

This math skill involves calculating the number of ways to arrange a word using letter tiles where some letters are duplicated. By using factorials, where each factorial represents possible arrangements of duplicate letters, the total arrangements are computed by multiplying these factorials.