Converting Other Bases To Decimal

Master the 'Positional Weight' multiplication method for converting binary, octal, or hexadecimal to decimal.

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Expanding the Puzzle

Hook about how positional values unlock the base-10 meaning.

Other Bases to Decimal

Imagine receiving a coded message in a foreign language. To translate a binary, octal, or hexadecimal number back into a format we understand (decimal), you have to expand it using its positional weights.

The value of every digit in a number depends on its position. By mapping out these positions, you can decode any base system into base-10.

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diagram

Binary to Decimal Breakdown

Visual calculation of 1101 binary to decimal.

clean scientific diagram, pastel color palette, elegant typography, precise labeling, white background, soft shadows. A structural diagram showing the calculation to convert binary 1101 to decimal 13 using positional weights. Top row shows digits 1, 1, 0, 1. Below them, position markers 3, 2, 1, 0. The next level displays positional values 2^3, 2^2, 2^1, 2^0. The bottom level shows the multiplication and addition: 1x8 + 1x4 + 0x2 + 1x1, culminating in a final sum of 13.
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Mapping binary digits to positional powers of 2 to find the decimal sum.

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Octal and Hexadecimal Examples

Explanation of applying this to base 8 and 16.

Applying the Rule

The beauty of the expansion algorithm is that it is universal. To convert base-8 or base-16 numbers to decimal, you simply swap the base multiplier to 88 (Octal) or 1616 (Hexadecimal).

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quiz

Try an Octal to Decimal Conversion

Convert 257 octal to decimal.

You are reading a low-level memory dump and come across an octal value that needs to be translated for a standard user interface. Following the expansion algorithm, convert the octal number (257)8(257)_8 into its decimal equivalent.