Number systems
Decimal and octal conversion worksheets
Practice decimal-to-octal and octal-to-decimal conversion with four ranges, 16 questions and printable answers. All selected ranges describe decimal values.
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Octal addition and subtraction worksheets
Practice vertical base-eight addition and subtraction with four operand ranges, 16 problems and optional answers. Generate a fresh printable set with the same settings.
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Calculate each result in base eight. Addition answers may exceed the chosen operand range; subtraction problems have positive answers.
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The range describes the operands
Choose addition only, subtraction only or a mixed sheet with eight of each. Addition results can exceed the selected range. Subtraction uses a larger first operand and a strictly positive difference.
The preview and downloaded PDF use the same questions. Include answers to append a separate key, or download just the student worksheet.
Learning objective
What this activity builds
Regroup in units of eight when adding or subtracting octal numbers.
Worked example
Add octal 57 and 26.
105 in base 8.
7 + 6 is decimal 13: write 5 and carry 1. The next column totals 5 + 2 + 1 = 8, so write 0 and carry 1 again.
Teaching notes
Make the practice count
- Regroup at eight, not ten.
- Keep the carried one separate from the original digits.
- Check each answer contains only digits 0–7.
- Use decimal values 47 + 22 = 69 to check the worked example.
Make it yours
Customize the practice
Choose your options, update the preview, then download the exact same pages.
Choose a range and operation profile. Every worksheet contains 16 reproducible tasks with a separate answer view.
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A useful next step
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