An excellent book for finding interesting maths challenges for students is Professor Stewart’s Cabinet of Mathematical Curiosities. They can be used for setting tasks that combine areas of maths knowledge and they also highlight to students that maths questions aren’t solved in seconds but require devising strategies to solve them. They are superb for developing deeper thinking skills.
One task in the book is called New Merology originally developed by Lee Sallows. The interactive whiteboard resource here supports demonstrating this puzzle to students. The challenge is to find a unique value for each of the letters in the spellings of the words zero to twelve so that when added up they equal the value of the word in which they are in. So the number chosen for the letter “O” added to the number chosen for the letter “N” added to the letter chosen for the letter “E” must add up to 1. Of course the letters appear in other words so by picking a value for “N” you also have an impact on the sum of the letters in “T+E+N”.
The resource allows you to chose a letter then select its value by dragging the red marker across the top. If any of the values you have chosen are duplicated a warning will show. The resource will also sum the values for each word. While this resource could be used to aid in the solving of the problem a more effective use is to just use it to demonstrate the problem to the class and to use it to discuss different approaches to the problem as it avoids lengthy recalculations when a value is changed. The student’s maths skills will be improved more if they work at the puzzle manually. This puzzle will then give them a practical application for their skills in adding negative numbers as well as the deeper thinking skills involved. A printable resource is also available below to give a structure to the puzzle. It may be useful to laminate the print out so that students can use non-permanent markers to to write with and rub out as they change values.
The solution will not be included here as it is available in the book Professor Stewart’s Cabinet of Mathematical Curiosities
and the intention here isn’t to take anything away from the book but rather support its use in the classroom. The range of values used in the solution is from -7 to 11 as shown in the resource.
Get printable resource.
To help you flesh out a lesson using this resouce and the benefits it has on learning there is a supprting article on teacherledplus.com.
Report any problems in the comments. Also, do you find resources such as this interesting or are the more usual teaching resources more useful?