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How to Do Division in Number Bases

Published in Number Base Division 3 mins read

Dividing numbers in different bases involves converting to base 10, performing the division, and converting back to the original base.

Understanding Division in Different Number Bases

The core challenge of dividing numbers in non-decimal bases (like binary, octal, or hexadecimal) is that our typical long division method is designed for base 10. The solution lies in performing calculations in a familiar system (base 10) and then converting back. This process simplifies the division for most people.

Steps for Division in Different Bases

Here's a structured approach, as explained in the provided reference, for performing division in different bases:

  1. Convert to Base 10: Change the numbers involved in the division from their original base to base 10. This step makes the math straightforward because we are proficient in base 10 calculations.

    • For example, if you need to divide 21 (base 3) by 2 (base 3):
      • Convert 21 (base 3) to base 10: (2 31) + (1 30) = 6 + 1 = 7 (base 10)
      • Convert 2 (base 3) to base 10: (2 * 30) = 2 (base 10)
  2. Perform Division in Base 10: Once both numbers are in base 10, perform the division as you normally would.

    • Following the previous example, 7 (base 10) divided by 2 (base 10) is 3.5 (base 10).
  3. Convert the Quotient Back to the Original Base: Take the base 10 result (the quotient) and convert it back to the original number base. If the result is a decimal, convert the integer and the decimal parts separately.

    • For our example, converting 3 (base 10) back to base 3:
      • 3 divided by 3 is 1 remainder 0 (so the least significant digit is 0)
      • 1 divided by 3 is 0 remainder 1 (so the next digit is 1)
      • So, 3 in base 10 is 10 in base 3. The result is 10.
  • If there is a decimal portion of the quotient that needs to be converted to the target base:
     *   Multiply the decimal portion of the base-10 quotient by the target base.
     *   Take the integer portion of the product and record it as the first digit after the decimal in the target base.
     *   Use the new decimal portion of the product for the next calculation and repeat the process until the decimal portion is zero or you have reached the desired level of precision.

Example Breakdown

Let's use an example that can be found in the provided reference to further illustrate. Suppose you want to divide 21 (base 10) by 3.

  • Base 10 Division: The reference says 21 divided by 3 equals 7.
  • Conversion The reference mentions needing to convert the base 10 result (7) back to a desired base. For example, to convert 7 to base 2:
    • 7 / 2 = 3 remainder 1
    • 3 / 2 = 1 remainder 1
    • 1 / 2 = 0 remainder 1
      Reading the remainders bottom to top gives us 111 in base 2.

Practical Insights

  • Understanding Place Values: A strong grasp of place values in different number bases is crucial for correct conversion between base 10 and the other bases.
  • Accuracy: When dealing with non-integer quotients, be mindful of the precision needed during the base conversion process.

Summary

Dividing numbers in non-decimal bases is easiest done by converting to base 10, performing division there, and then converting the quotient back to the original base. This method leverages our familiarity with base 10 arithmetic.

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