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 says that the number is even, for example, then you need to mark off the odds). Some of the kids got the idea quickly; many of them did not. Of course, then the clues got harder (“if you add the digits, the sum is 12,” for example). They worked hard and with great enthusiasm (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 one and only one 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 told the kids they need to practice to be sure that their clues actually lead to one (and only one) number. It might be a good idea to make copies of the hundreds chart, in case they need to practice more than once.
This activity was “confusing, and hard, and SO FUN” according to one of the first graders. I would say this is a pretty accurate summation of how most of the kids felt. Your child may need some help creating his/her clues and practicing to make sure they only lead to one number.
You can find the packet at this link (Secret Number), if you need another hundreds chart or more cards.