fix typo in bit.md (#338)

diff --git a/docs/math/bit.md b/docs/math/bit.md
index 2348a53..19600f5 100644 (file)
--- a/docs/math/bit.md
+++ b/docs/math/bit.md
@@ -63,7 +63,7 @@ $$
 $$\r
 \begin{aligned}\r
 &5&&=&&(101)_2\\\r
-&5\tt\,\&\,\rm2&&=&&(10100)_2\!\!\!&=&&\!\!\!20\\\r
+&5\tt\,<<\,\rm2&&=&&(10100)_2\!\!\!&=&&\!\!\!20\\\r
 &5\tt>>\rm1&&=&&(10)_2&=&&2\r
 \end{aligned}\r
 $$\r