posted by charlie .
kirk grew a crystal in science class. On monday it was 13/16 inch tall. it had grown 1/4 inch bet friday and monday. It had grown 1/2 inch between Tues and Fri. How tall was Kirk'a crystal on Tues?
With the way you have phrased your question, I am not sure what you are asking.
If it was 13/16 inches tall on Monday, and there is no indication of growth between Monday and Tuesday, it is still 13/16 inches tall.
I hope this helps. If not, repost in clearer terms. Thanks for asking.