Issue 22465: grammar, number agreement.

Doc/reference/datamodel.rst

@@ -222,7 +222,7 @@ Ellipsis
       at the mercy of the underlying machine architecture (and C or Java
       implementation) for the accepted range and handling of overflow. Python does not
       support single-precision floating point numbers; the savings in processor and
-      memory usage that are usually the reason for using these is dwarfed by the
+      memory usage that are usually the reason for using these are dwarfed by the
       overhead of using objects in Python, so there is no reason to complicate the
       language with two kinds of floating point numbers.