This is one of my favorite tricks.
First, write the number 68 on a piece of paper and seal it in an envelope.
Then tell the students that you are going to have them pick any five numbers from
the following table of 25 numbers, and you are going to predict the sum.
Give the envelope with your prediction to a student to hold.
The only restriction about picking numbers is that once they have picked a number
from a particular row and column, they cannot pick another number from either
that row or that column.
| 6
|
5
|
7
|
9
|
10
|
| 13
|
12
|
14
|
16
|
17
|
| 11
|
10
|
12
|
14
|
15
|
| 22
|
21
|
23
|
25
|
26
|
| 9
|
8
|
10
|
12
|
13
|
When a student selects a number from the table, I circle that number and cross out the
other numbers in that row and column.