Covered by H

Use a hundred square or chart to count by ones and tens, starting from any number. Cover one number and ask the students what is covered and how they know. Gradually cover more numbers.

Show the following image. Explain that it is a section of a hundred square that has been partly covered by an H-shape.

Numbers covered by H.

Ask the students to name the covered numbers and explain their reasoning. Then ask them to identify what is the same and what is different about the numbers, horizontally and vertically.

Move the H-shape to another area and sketch the section of the hundred square.

Focus the discussion on students' reasoning.

• Why?
• How do you know?
• What if …? What if …, not …?
• Where would …?
• When could …?
• If …? If … then …?
• How could you describe the rule or pattern …?
• What could …?

Other shapes and starting points could be used with different year levels. This activity is adaptable for Number and Algebra from years 1–10. For some suggestions, you can download Other Covering Shapes.