Number systems
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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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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Start with a ready-made worksheet
Convert eight decimal numbers to octal, then convert eight octal numbers to decimal. An octal digit can only be 0 through 7.
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One value, two representations
Each sheet has eight questions in each direction. The selected decimal interval applies to the value, whichever base is printed in the question. Both endpoints are included so that the smallest and largest representations receive practice.
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
Use powers of eight to convert whole numbers between decimal and octal.
Worked example
What is octal 123 in decimal?
83.
Read the places as 64, 8 and 1: 1 × 64 + 2 × 8 + 3 = 83.
Teaching notes
Make the practice count
- Label the places 1, 8, 64 and 512 from right to left.
- Check that no octal answer contains 8 or 9.
- Treat the selected range as a decimal value range in both directions.
- Connect one octal digit to a group of three binary digits.
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.
Enlarged pages scroll. PDF size stays the same.
A useful next step
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