### Lesson plan

# Solving KenKen Puzzles

#### Learning Objectives

Students will be able to apply logic and their knowledge of addition, subtraction, multiplication, and division to solve KenKen grid puzzles.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.

#### Introduction

*(3 minutes)*

- 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.

#### Differentiation

**Support:**

- 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.

**Enrichment:**

- 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).

#### Assessment

*(12 minutes)*

- 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.