diff --git a/docs/usage.md b/docs/usage.md
index b80b649..22047c3 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -24,6 +24,5 @@ myvar = (2+2)
 
 ## Built-in variable
 
-- `ans` is the last calculation done
-- `pi` is pi 
-- `e` is e
\ No newline at end of file
+- `pi` is pi as a double precision float
+- `e` is e as a double precision float
\ No newline at end of file