diff --git a/app/views/play/level/tome/SpellView.coffee b/app/views/play/level/tome/SpellView.coffee
index 9cddc2178..cd7cc1c18 100644
--- a/app/views/play/level/tome/SpellView.coffee
+++ b/app/views/play/level/tome/SpellView.coffee
@@ -316,7 +316,7 @@ module.exports = class SpellView extends CocoView
 
             xstart = startOfRow(row)
             if language is 'python'
-              requiredIndent = new RegExp '^' + new Array(xstart / 4 + 1).join('(    |\t)') + '(    |\t)+(\\S|\\s*$)'
+              requiredIndent = new RegExp '^' + new Array(Math.floor(xstart / 4 + 1)).join('(    |\t)') + '(    |\t)+(\\S|\\s*$)'
               for crow in [docRange.start.row+1..docRange.end.row]
                 unless requiredIndent.test lines[crow]
                   docRange.end.row = crow - 1