Solution 12661: Order of Operations and Exponents Utilized by TI Graphing Calculators.
What order of operations or exponents cause Texas Instruments graphing calculators to evaluate 2^3^4 as (2^3)^4 instead of 2^(3^4)?
Entering 2^3^4 causes the calculator to interpret what the expression really means, and there are three schools of thought regarding this:
1) Associate left to right. The TI-8X series graphing calculators which includes the TI-Nspire™ Handheld in TI-84 Plus mode, with the exception of the TI-89 family, follow this strategy. This convention relies on the user to clear up questionable areas with parentheses.
2) Associate right to left. The TI-89 family, TI-92 family, Voyage™ 200, TI-Nspire CAS and DERIVE perform this.
3) Have the device or software return a syntax error until parentheses are given.
It is recommended to always use parentheses where the rules of algebra may not be clear.
For more information regarding your Texas Instruments graphing calculator, please refer to the guidebooks section.