Hidden Numbers

What You Need:

• 4 envelopes all of equal size, brown mailing envelopes work well
• 9 pieces of white paper cut to fit these envelopes
• A heavy, black marker
• Scissors
• Extra paper
• Pencil

What You Do:

1. Cut a window into the bottom left corner of the first envelope (see photo).
2. In the next envelope, cut a window in the bottom right corner. For the third, cut a window in the top right corner. For the fourth, cut a window in the top left corner.
3. Use the marker to write “Guess the Hidden Number” on each envelope.
4. Draw a large number on each piece of paper. Start with 1 and continue through 9. Be sure to position the 1 so that it will show through at least two of the windows.
5. Randomly sort your pile of numbered pages so that you won’t be working from 1 through 9. 
6. Slip one of the numbers into one of the envelopes.
7. Show it to your child. Can she tell you what number it is? Be prepared to discuss what your child can see through the window. A horizontal line in the top right window can belong to a 5 or a 7.
8. Give your child a piece of paper and the pencil. Help her draw a grid of four squares and have her copy what she sees through the envelope window into the appropriate square.
9. Now slip the number into another one of the envelopes. This will give your child a different view. Again, have her draw what she sees. What number does she think it is now?