# Enter "undefined" in self checking table

**URL:** <https://cl.desmos.com/t/enter-undefined-in-self-checking-table/1395>\
**Category:** Questions\
**Created:** [August 29, 2020, 7:00pm UTC](https://cl.desmos.com/t/enter-undefined-in-self-checking-table/1395 "2020-08-29T19:00:03Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Bsamuels](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/bsamuels/32/872_2.png) [@Bsamuels](https://cl.desmos.com/u/Bsamuels)\
**Post date:** [August 29, 2020, 7:00pm UTC](https://cl.desmos.com/t/enter-undefined-in-self-checking-table/1395/1 "2020-08-29T19:00:03Z")

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In prompting students for an answer in a table where the value is undefined, how do I adjust the code to read text rather than a number and if a number is entered, an error is displayed?