This activity is great for place value and hundreds chart practice. It includes 50 numbered cards where students are asked to locate the mystery number which is marked with a question mark. A recording sheet is included for accountability purposes if you wish to use it. An answer key is also included for this component. An additional 30 cards are also included that do not have a specific square marked. I tend to use these cards initially and ask students to record all the numbers - counting by tens and ones. I then introduce the numbered cards and ask them to count and point rather than writing all the numbers. I made this set in a detective/police theme - my kids love solving the mystery numbers. I hope you find this activity useful.