Exception

======== Exception caught by rendering library ===================================================== The following assertion was thrown during performLayout(): BoxConstraints forces an infinite height. These invalid constraints were provided to RenderFlex's layout() function by the following function, which probably computed the invalid constraints in question: RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:277:14) The offending constraints were: BoxConstraints(w=124.3, h=Infinity) The relevant error-causing widget was: SizedBox.expand SizedBox:file:///C:/Users/Eddy/StudioProjects/kidmath/lib/math/addition_page.dart:385:32 When the exception was thrown, this was the stack: #0      BoxConstraints.debugAssertIsValid..throwError (package:flutter/src/rendering/box.dart:516:9) #1      BoxConstraints.debugAssertIsValid. (package:flutter/src/rendering/box.dart:560:11) #2      BoxConstraints.debugAssertIsValid (package:flutter/src/rendering/box.dart:564:6) #3      RenderObject.layout (package:flutter/src/rendering/object.dart:1784:24) #4      RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:277:14) #5      RenderObject.layout (package:flutter/src/rendering/object.dart:1887:7) #6      ChildLayoutHelper.layoutChild (package:flutter/src/rendering/layout_helper.dart:56:11) ...

Error

You should use Expanded widget within Row(), Column(), or Flex().