fixing typos

Author: howcome

css-multicol/Overview.src.html

@@ -567,8 +567,8 @@ <h2>The number and width of columns</h2>
 <p>A third property, 'columns', is a shorthand property which sets both
 'column-width' and 'column-count'.
 
-<p>Other factors, such as the explicit column breaks and height
-constraints, may influence the actual numer and width of columns.
+<p>Other factors, such as explicit column breaks and height
+constraints, may influence the actual number and width of columns.
 
 
 <h3 id='cw'>'column-width'</h3>