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Unit 8 Review

Unit 8 Day 6
CED Topic(s):
3.13, 3.14, 3.15


Crack the Code! is an engaging activity for students to play in groups. A four-digit code is required to successfully complete the game. Students discover each digit by identifying true and false statements in four sets of questions designed to review the main concepts in Unit 8.

Activity: Crack the Code



Lesson Handout

Answer Key


Prep: Place copies of Problem Sets A-D at the front of the room on four piles.

Play: Have one member from each group grab the Set A problems and have all students work in their group to solve the first question. Students should tally how many of the 9 statements they have marked TRUE. This will be the first digit of the code. When they have finished, they should pick up Problem Set B and continue in the same fashion. Handing out all the problems at once tends to discourage group work and lead students to a divide-and-conquer approach.

Once students have solved all four questions, they should write their four-digit code on the board. As the teacher, you should only tell them if it is correct or incorrect (we don’t tell them how many of the digits are incorrect!). Once a group has posted a code, they cannot give another guess until at least two groups have written up a code. This is to reduce trial and error approaches. The first group to arrive at the correct code wins. You may wish to reward a small candy prize. Students are engaged in this activity and minimal direction is needed. Our students had written more than 12 codes on the board before the correct code was found! Get ready to hear plenty of peer-to-peer discussion!


At the end of the activity, review the four problems and answer any remaining questions. Note that even if a group found the correct number of true answers, they may not have picked all the correct statements, so it is worthwhile to review which answers were true. You could have groups take turns presenting the problems and their thought process if time permits.

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