You need to hold ⇧ and press the other key for the 2nd function.

It’s easier to tap the same key twice for the 2nd function.

Magic Number  ▸  Preferences… ▸  Shortcuts

In general, any function that requires pressing the shift (⇧) key can be accessed via Double Key.

Trigonometry

S=sin	SS=sin⁻¹
C=cos	CC=cos⁻¹
T=tan	TT=tan⁻¹

Exponents

Y=xY	YY=x1/Y
Z=x2	ZZ=x3
J=√	JJ=n√
E=ex	EE=2x	EEE=10x
L=log	LL=log₂	LLL=log₁₀

Tax*

V=tax

VV=tax2

VVV=tax3

* Shortcut and names are customizable. See here.

Memory

A=a	AA=a2
B=b	BB=b2
K=k	KK=k2
M=m	MM=m2
N=n	NN=n2

The buttons  F 1  and F 2 can be customized with extra functions (see here).

Their keyboards shortcuts are F1 and F2.
You may find it easier to use F and G instead.

If you right-click or control click  F 1 , you get a menu of functions with the related ones grouped together:

You can use Double Key to access related functions.
For example:

If:	Then:
F1=Modulo	F1F1=Quotient
F1=Percent Change	F1F1=As Percentage Of
F1=Combinations	F1F1=Permutations
F1=Round	F1F1=Truncate

It works the other way too. If  F1 = Quotient, then F1 F1 = Modulo. The same applies to F2.

Note:  The keys F1 and F2 are often used by OS X.
We recommend you use F and G.