Binary and number bases · Year 13

In Year 13 you get fluent with: bases in computing.

We count in tens because we have ten fingers, but any whole number can be written in any base. Computers use base 2 (binary), and programmers use base 16 (hexadecimal) as a compact way to write binary. Converting between bases is all about place value.

Key facts

  • In base b the columns are worth 1, b, b², b³, … from the right, and the digits run from 0 to b − 1.
  • To convert to denary, multiply each digit by its column value and add.
  • From denary, divide repeatedly by the base. The remainders, read from the bottom up, are the digits.
  • n bits can store 2ⁿ different values, from 0 to 2ⁿ − 1.

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