Turn addition practise into an exciting mathematical investigation with our Addition Sleuth: Addition to 20 Worksheets! This engaging resource challenges students to become number detectives as they search for pairs of numbers that add up to a target sum. It’s a fantastic way to consolidate addition facts, promote flexible thinking, and build confidence with number combinations - all while having fun!

Each worksheet features a target number and a grid full of potential addends. Students search the grid to uncover number pairs that match the target sum, shading the correct pairs as they go. With 20 pairs to find on each worksheet, this activity promotes repeated practise and encourages students to apply strategic thinking. It’s ideal for supporting fluency, reinforcing number bonds, and extending students’ understanding of partitioning numbers to 20.

Addition Sleuth: Addition to 20 Worksheets are perfect for use as an independent maths activity, in small group rotations, or as part of your warm-up or early finisher options. The investigative nature of the task promotes persistence, problem-solving, and critical thinking - all key mathematical skills for young learners. Plus, the visual aspect of shading the grid adds an element of fun and satisfaction as students work through each sheet.

Key Learning Outcomes:

• ✅ Develop fluency in addition facts to 20
• ✅ Strengthen understanding of number bonds and partitioning
• ✅ Promote flexible thinking and strategic problem-solving
• ✅ Build visualisation of number relationships through grid work
• ✅ Foster mathematical confidence and perseverance

What’s Included:

• Target number worksheets with numbers up to 20
• Each worksheet features a number grid and checklist
• Teacher tips for classroom use and extension

Materials Needed:

• Printed Addition Sleuth worksheets
• Coloured pencils, crayons, or markers for shading addends
• Optional manipulatives - ten frames, counters, or blocks for additional support
• Timers (optional) for timed challenges

How to Use:

1. Print the Addition Sleuth worksheets and distribute to students.
2. Explain that each worksheet has a target number displayed in the top right corner.
3. Students search through the grid to find pairs of numbers that add up to the target number.
4. They shade the two addends in the grid and tick them off on the provided checklist.
5. Encourage students to use different colours for different pairs to visually track their progress.
6. Support students as needed with manipulatives or number lines to represent the addition problems.

Ideas for Classroom Use:

• 💡 Include in your daily maths warm-ups to reinforce number bonds.
• 💡 Use during small group instruction to support strategic addition practise.
• 💡 Set up as an independent activity for early finishers.
• 💡 Create a fun "Sleuth Challenge" where students race the clock to find all 20 pairs.
• 💡 Encourage students to explore beyond pairs by finding combinations of three addends that match the target sum.

Top Teacher Tips:

• 💛 Provide ten frames, counters, or blocks for students who benefit from tactile or visual supports.
• 💛 Use highlighters or different coloured markers to keep the grid organised and visually engaging.
• 💛 Differentiate by providing worksheets with different target numbers based on student readiness.
• 💛 Extend learning by asking students to create their own Addition Sleuth puzzles for classmates to solve.

Addition Sleuth: Addition to 20 Worksheets offer a creative, interactive way to build addition fluency and number sense. Students will love the challenge of finding number pairs, while teachers will love how this resource supports mathematical thinking, perseverance, and flexibility!