What is "one of two numbers whose product is one". It's in a crossword, 21 letters, 4th letter is "T". Please help!

how about

multiplicative inverse ?

To find the answer to the crossword clue "one of two numbers whose product is one," we can follow these steps:

1. Start by looking for words that have 21 letters and have the 4th letter as "T".
2. One possibility is the word "reciprocal."
3. The word "reciprocal" fits the description of "one of two numbers whose product is one" because the reciprocal of a number is the value that, when multiplied by the original number, gives a product of one.
4. Verify if "reciprocal" fits in the crossword puzzle by cross-checking with the intersecting letters from the other words already filled in.

So, the answer to the crossword clue "one of two numbers whose product is one" with 21 letters and the 4th letter as "T" is likely to be "reciprocal."