You may wish to group your students in pairs to carry out the activity. Later
on students may choose to work independently to create codes for their friends
Tell the students that they are going to create a variable machine to
discover the value of words. On the three-centimeter-wide strip of lined
notebook paper, have them write the letters of the alphabet in order down the
left side of the paper.
Down the right side of the five-centimeter strip of notebook paper, have them
write the numbers from 0 to 25. They should then attach the ends of the number
strip together with a piece of tape; wrap the letter strip around the number
wheel, matching the letters to the corresponding numbers:
A to 0
B to 1
C to 2
and so on....
and tape the ends of the letter strip together, as shown below:
A Completed Variable Machine
Have the students find the value of their first names, using their variable
machines; for example, the value of Amy's name is 36:
A = 0, M = 12, Y = 24
0 + 12 + 24 = 36
Have the students find the value of their last names, and ask the following
- Which name has the higher value - your first name or last name?
- What is the difference in the values of your first and last names?
Students should explore the values of various words. For example, ask students to find words:
- Whose values are equal to 25, 36, or 100?
Ask, "Do most of the
words you checked have a value that is even or odd?" Students should discuss strategies they might use to answer this question.
These questions and activities are also found on the Cracking the Code Activity Sheet. Students can record their findings on the activity sheet.
Cracking the Code Activity Sheet
As students find the values of various words, ask questions
- What is the three-letter word with the greatest value?
- Are the greatest values always associated with words that contain the most