Solving KenKen Puzzles
Students will be able to apply logic and their knowledge of addition, subtraction, multiplication, and division to solve KenKen grid puzzles.
- Ask students to brainstorm different types of puzzles they have worked with (e.g., jigsaw puzzles, tangrams, and word puzzles).
- Tell students that today we are going to work with a type of grid puzzle called KenKen puzzles.
- Explain to students that while working with puzzles is very fun, they are also a great way to practise our maths skills such as logic, problem solving, addition, subtraction, multiplication, and division.
Explicit Instruction/Teacher modeling(10 minutes)
- Show students an example of a KenKen puzzle by displaying the KenKen: Dragon worksheet on the document camera.
- Tell students this is an example of a KenKen puzzle.
- Call on students to share their observations about this puzzle (e.g., it has a 4x4 grid, areas of the grid have a border around them, and there are different numbers and maths operations on the grid).
- Post a piece of chart paper on the board to be used as a reference throughout this lesson. Title this chart paper "Rules for KenKen" and write the rules. Tip: point to the different parts of the KenKen: Dragon worksheet as you are writing each rule.
- The only numbers you can use are 1, 2, 3, or 4 (a 5x5 puzzle uses numbers 1–5).
- No numbers can appear more than once in any row or column.
- Areas, called cages, have a dark border around them and have a target number. If there is more than one square in the cage, the target number also has a maths operation. Fill in the square with numbers that produce the target number using the indicated operation.
- In a one-square cage, just write the target number in that square.
Guided practise(15 minutes)
- Refer back to the KenKen: Dragon worksheet on the document camera.
- Tell students that we will complete this puzzle as a class.
- Model for students how to look for the easiest place to start the puzzle, which is the one-square cage.
- Call on students to identify any one-square cages, if any.
- Model for students how to look for cages where there is only one solution (e.g., a 3+ cage can only mean numbers 1 and 2).
- Call on students to identify any cages with one solution.
- Model for students how to look for cages where the target numbers are high or low given the number of squares in the cage (e.g., a 4x4 puzzle with the target number of 6+ can only mean numbers 1, 2, and 3).
- Call on students to identify any cages with high or low target numbers.
- Invite students to share other strategies as you complete this puzzle together.
Independent working time(15 minutes)
- Tell students they will now practise this skill independently.
- Preview and distribute the Baseball KenKen Puzzle worksheet.
- Remind students to use the Rules for KenKen as a reference when they are completing this grid puzzle.
- Circulate and offer support as students are working independently.
- Pre-teach a lesson on grid puzzles using a 3x3 grid.
- Write out the rules for KenKen on individual pieces of paper to distribute to students to keep at their desks to use throughout the lesson.
- Provide students with a partially completed copy of the KenKen: Baseball worksheet during Independent Work Time.
- Allow students to work with KenKen: Tiger, a 3x3 grid using addition and subtraction (see optional materials).
- Gather students into a teacher-led small group to complete KenKen: Baseball with support during Independent Work Time.
- Challenge students by providing them with KenKen: Roller Skating, a 6x6 grid with addition, subtraction, multiplication, and division (see optional materials).
- Encourage students to use graph paper to create their own KenKen puzzle to exchange with a partner. Challenge students to create puzzles with 6x6 grids that incorporate addition, subtraction, multiplication, and division (see optional materials).
- Show students the partially completed KenKen: Magic worksheet on the document camera.
- Tell students that they will complete this puzzle by filling in the remaining squares on their copy of the worksheet.
- Distribute KenKen: Magic to each student.
- Collect students' puzzles when they are done.
Review and closing(5 minutes)
- Tell students that solving KenKen puzzles is not only a fun activity but it is also great for our brains.
- Ask students to turn to a partner to brainstorm the different ways that grid puzzles are good for our brains.
- Guide students to understand that working with puzzles helps to build students' logic skills, problem-solving skills, mathematical operations skills, and interest/motivation in maths.