To represent the formula in mathematical form, the calculator uses a combination of the characters in linear mode (√(, ^(, ∑( and others), the box character, and 6 characters (called ABCDEF)

In ES PLUS calculators, the characters are the same as the 6 hexadecimal characters used in base-N mode (displayed as bold A - F in linear mode), and it's possible to evaluate them in modes other than base-N to give unexpected result. (Note that storing some invalid values in the variables may reset the calculator on boot)

In Classwiz calculators, they have hexadecimal values 1A - 1F (displayed as = in linear mode)

Some invalid representation of the special characters may crash/hang the mathematical formula renderer (in math mode)

All representations:

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