Solution 11648: Printer Display Calculator Will Not Add Or Subtract.
Why won't my printing calculator add or subtract?
In general, a printing calculator will not add or subtract if the [Calc/Tax] key is set to [Tax]. The printing calculator should function as expected once the switch is moved to [Calc].
If this does not return the unit to proper operation, please contact TI-Cares to get further assistance.
Note: Texas Instruments discontinued the entire line of printing calculators more than 15 years ago. For this reason, support and/or replacement for this type of product is not available.