diff --git a/content/arrays.md b/content/arrays.md
index e401253..c77329f 100644
--- a/content/arrays.md
+++ b/content/arrays.md
@@ -18,7 +18,7 @@ The size of the array is encoded in its type and cannot be accidentally lost. Th
 ``` nimrod
 proc zip[I, T](a, b: array[I, T]):
                array[I, tuple[a, b: T]] =
-  for i in low(A)..high(A):
+  for i in low(a)..high(a):
     result[i] = (a[i], b[i])
 
 let nameAndAddresses = names.zip(addresses)
@@ -61,4 +61,4 @@ $ nim c -r matrix.nim
 1, 1, 
 1, 1, 
 
-```
\ No newline at end of file
+```