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 1?

    • 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 a NOT gate, and its output meets B in an AND gate. With A = 1 and B = 1, what comes out?

    • 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. Do the boots go on?

    • Yes
    • No
    • Only at night

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

    • AND
    • OR
    • NOT

  8. A friend starts at the last gate of a two-gate chain and gets lost. What method 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 1 1 row outputs 1.
  2. 0 · NOT flips its single input, so 1 becomes 0.
  3. True · OR needs at least one input at 1. Only the 0 0 row outputs 0.
  4. 0 · NOT flips A to 0, and 0 AND 1 gives 0.
  5. 1 and 1 · AND outputs 1 only when both inputs are 1.
  6. Yes · The rule is an OR, and one true input is enough for OR.
  7. AND · Both conditions must hold at once, which is what AND does.
  8. Trace forward one gate at a time · Start at the gates nearest the inputs and write each output on its wire.
Worksheet · LightMySky