\documentclass[varwidth=256px]{standalone}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{xcolor}

\definecolor{chalkwhite}{RGB}{240, 250, 245}
\definecolor{chalkred}{RGB}{255, 119, 122}
\definecolor{chalkorange}{RGB}{255, 195, 128}
\definecolor{chalkyellow}{RGB}{244, 244, 120}
\definecolor{chalkgreen}{RGB}{135, 230, 121}
\definecolor{chalkblue}{RGB}{128, 195, 255}
\definecolor{chalkpurple}{RGB}{206, 168, 238}
\definecolor{chalkpink}{RGB}{240, 157, 215}

\newcommand{\chalk}[1]{\color{chalk#1}}

\chalk{white}