# Formula Parsing VI Variables

The Formula Parsing VIs accept only the following variables:

*a*, *a0*, ..., *a9*

*b*, *b0*, ..., *b9*

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.

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*z*, *z0*, ..., *z9*

Note For variable and function names, only lowercase letters are allowed. The VIs interpret capital letters as errors. |

All numbers in exponential notation use the 1E–1 convention with the capital letter E. Using 1e–1 with the lowercase letter e results in an error message.