This is a fun number sense activity for students. It can be used as morning work, at a math station or for homework. "Guess My Number" and "Name Collection Boxes" are integrated into one easy activity that covers many of the common core standards. Each number has 2 pages for a total of 20 pages. There is also a second version that is exactly the same except the number line does not have any numbers on it. Using an "Open Number Line" is a math strategy that we are trying to get our students to use. This is also a 2nd grade common core standard. I wanted to provide both options since some of my students need the numbers provided when they are learning to count.
In the first part where students use the clues to find the mystery number, I have a number Iine with the possible numbers on it and a 100s chart. I have both because I want my students to see the connection between the number line and the 100s chart. We do the clues together. I have students cross out numbers on the number line as they are eliminated by the clues. They circle the final answer. They also may highlight possible numbers on the 100s chart from the first clue and do same process as the number line until the mystery number is discovered.
Students must show the mystery number using:
* Place Value
* Ten Frame
* Number Bond
* Ten More/ Ten Less
* Number Before and Number After
I have students write the number bond that matches the ten frame. They use a red and blue crayon to make the ten frame. If the Mystery Number is 7 and they did 3 blue and 4 red, they need to write 3 and 4 in their number bond. I do this so they make the connection between the Ten Frames and Number Bonds.
Students can draw or use stamps for the coins and base ten blocks. I have them write the total value above the coins and base ten blocks as they count them.
**** This is the fourth set of Case of the Mystery Number. I will add more sets with skills progressing based on common core standards.