added proof bit

[tt1516.git] / mbt_exercises / pre.tex

diff --git a/mbt_exercises/pre.tex b/mbt_exercises/pre.tex
index 59d2e91..723347a 100644 (file)
--- a/mbt_exercises/pre.tex
+++ b/mbt_exercises/pre.tex
@@ -1,7 +1,8 @@
-\documentclass{article}
+\documentclass[twocolumn]{article}
 
 \usepackage{enumerate}
 \usepackage{amssymb}
+\usepackage{cancel}
 \usepackage{amsmath}
 \usepackage{a4wide}
 \usepackage{xypic}