Power with a natural exponent.
Definition:
[tex]a^2=a\cdot a\\\\a^3=a\cdot a\cdot a\\\\a^4=a\cdot a\cdot a\cdot a\\\vdots\\a^n=\underbrace{a\cdot a\cdot a\cdot...\cdot a}_{n}[/tex]
also
[tex]a^1=a\\\\a^0=1[/tex]
[tex]6^1=6\\\\3^2=3\cdot3=9\\\\2^3=2\cdot2\cdot2=8\\\\1^7=1[/tex]
therefore
[tex]\huge\boxed{1^7 < 6^1 < 2^3 < 3^2}[/tex]
