Skip to main content\(\newcommand{\N}{\mathbb N} \newcommand{\Z}{\mathbb Z} \newcommand{\Q}{\mathbb Q} \newcommand{\R}{\mathbb R}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\)
Chapter 4 STACK questions not yet added
Checkpoint 4.0.1.
Checkpoint 4.0.2.
Checkpoint 4.0.3.
Checkpoint 4.0.4.
Checkpoint 4.0.5.
Checkpoint 4.0.6.
Checkpoint 4.0.7.
Checkpoint 4.0.8.
Checkpoint 4.0.9.
Checkpoint 4.0.10.
Checkpoint 4.0.11.
Checkpoint 4.0.12.
Checkpoint 4.0.13.
Checkpoint 4.0.14.
Checkpoint 4.0.15.
Checkpoint 4.0.16.
Checkpoint 4.0.17.
Checkpoint 4.0.18.
Checkpoint 4.0.19.
Checkpoint 4.0.20.
Checkpoint 4.0.21.
Checkpoint 4.0.22.
Checkpoint 4.0.23.
Checkpoint 4.0.24.
Checkpoint 4.0.25.
Checkpoint 4.0.26.
Checkpoint 4.0.27.
Checkpoint 4.0.28.
Checkpoint 4.0.29.
Checkpoint 4.0.30.
Checkpoint 4.0.31.
Checkpoint 4.0.32.
Checkpoint 4.0.33.
Checkpoint 4.0.34.
