Fraction is centered:

 1 2 3 4

×

 1 2 3 4

 1 2 3 4

You can see arrows:

 ◂ 1 × 2 × ⋯ × n
\overleftarrow

 ▸ 1 × 2 × ⋯ × n
\overrightarrow

The arrow extends properly

 ▸ 1234567890

The arrows extend properly

α
 ▸ 1234567890
β
 ◂ 9876543210
γ

This document was translated from LATEX by HEVEA.