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Grade 8 Computer Science — Hexadecimal numbers

Read a hexadecimal number, turn it into decimal or into binary, and say why programmers write bits this way.

Name: ________________________

  1. 1.Match each hexadecimal digit to the four bits it stands for.

    • 4
    • 7
    • 9
    • D
    • E
    • 1101
    • 0111
    • 1001
    • 0100
    • 1110

  2. 2.Write the decimal number 45 in hexadecimal. Use two hexadecimal digits.

  3. 3.Two hexadecimal digits are written side by side. What is the largest decimal number the pair of them can hold between them?

    • a) 255
    • b) 256
    • c) 128
    • d) 99

  4. 4.Put these hexadecimal numbers in order, smallest first.

    • B0
    • 2A
    • 1F
    • 4D
    • FF

  5. 5.Only one of these four is not a hexadecimal number at all. Which one?

    • a) 3G4
    • b) 72E
    • c) 9FB
    • d) A0C

  6. 6.Which point on the line is the hexadecimal number 3A written in decimal?

    Mark the line with an X.

    01020304050607080

  7. 7.Sort each hexadecimal number by whether it comes to more than 100 in decimal.

    Groups: More than 100 · Less than 100

    • 5F
    • 40
    • C0
    • 7A
    • AA
    • 3C

  8. 8.Write the hexadecimal number A7 as eight binary bits.

Answer key — Grade 8 Computer Science — Hexadecimal numbers

  1. 1. 4 → 0100; 7 → 0111; 9 → 1001; D → 1101; E → 1110
  2. 2. 2D
  3. 3. a) 255
  4. 4. 1. 1F 2. 2A 3. 4D 4. B0 5. FF
  5. 5. a) 3G4
  6. 6. 58
  7. 7. 5F → Less than 100; 7A → More than 100; 3C → Less than 100; C0 → More than 100; AA → More than 100; 40 → Less than 100
  8. 8. 10100111