doc/tutorial/basics: some documentation improvments

Change-Id: I9594d34547b11a38619b74001c42e35950feb6c4
diff --git a/doc/tutorial/basics/rangedef.md b/doc/tutorial/basics/rangedef.md
index 6bb34eb..31f7ce8 100644
--- a/doc/tutorial/basics/rangedef.md
+++ b/doc/tutorial/basics/rangedef.md
@@ -2,7 +2,7 @@
 
 # Predefined Ranges
 
-Numbers if CUE have arbitrary precision.
+CUE numbers have arbitrary precision.
 Also there is no unsigned integer type.
 
 CUE defines the following predefined identifiers to restrict the ranges of