This week in first grade math, we worked on using clues to locate a “secret number” on a hundreds chart. I gave the kids four clues for each number. As they received the clues, they used dry erase markers to eliminate numbers on the chart that could not be the secret number. For example, if the clue was “the number is odd,” then the kids crossed off all of the even numbers. This is a bit more confusing than perhaps it sounds, because one has to be careful to be sure to mark off the inverse of the clue (if it say even, mark the odds). Most of the kids got the idea quickly. Of course, then the clues got harder (“if you add the digits, you get 12,” for example. They worked hard (for some of them, it was almost equally difficult not to shout out the number as soon as they found it).
Homework is to create a set of four clues that lead to a secret number. All of the clues should be necessary to find the number, and they should lead to only one number. I sent home a hundreds chart to help. Please do not cut out the clue cards — keep them as a whole sheet, turn them in and let me check them, and then we will use them in class the next time we play “Secret Number.”
I was taking pictures today and these two of the long sides of the big table made me laugh. I felt like I was seeing double… twice!