Logic Gates and Truth Tables · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Yes, no, and both at once

Computing · Computer Systems · ages 15-16
Name ______________________   Date ____________

  1. In the AND truth table, how many rows output true?

    • Two
    • Four
    • One

  2. What does a NOT gate output for input 1?

    • 1
    • 0
    • Both

  3. An OR gate outputs 1 when either input is 1.

    Circle one:   True   False

  4. A feeds NOT, whose answer meets B in AND. With A = 1 and B = 1, what exits?

    • 1
    • 0
    • Nothing

  5. Which input pair makes AND output 1?

    • 1 and 0
    • 1 and 1
    • 0 and 0

  6. Boots go on for rain or hiking. No rain today, but hiking is on. Boots?

    • Yes
    • No
    • Only at night

  7. Graduation needs GPA above 2.0 and 120 units. Which gate matches the rule?

    • AND
    • OR
    • NOT

  8. A friend traces a two-gate chain from the last gate backwards and tangles. What fixes it?

    • Guess the output from the inputs
    • Swap the gates around
    • Trace forward one gate at a time
LightMySky · lightmysky.comW1-mt_o2N0-q3A4Q-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Yes, no, and both at once W1-mt_o2N0-q3A4Q-s1

  1. One · Only the both-true row answers true.
  2. 0 · NOT inverts its single input, so 1 becomes 0.
  3. True · Only the both-off row answers 0.
  4. 0 · NOT flips A to 0, and 0 AND 1 answers 0.
  5. 1 and 1 · AND answers 1 only when both wires are on.
  6. Yes · One true input already satisfies an OR.
  7. AND · Both conditions must hold at once, which is exactly AND.
  8. Trace forward one gate at a time · Writing each gate's output on its wire untangles any chain.
Worksheet · LightMySky