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Truth Table Workshop

Deep inside a computer, logic gates make decisions with just 1s and 0s. Learn the AND, OR and NOT operators, fill in truth tables row by row, and build up a combined expression systematically.

⏱️ 18 min 🎯 14 activities Teachers Not yet rated Students Not yet rated

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What you'll cover

Logic in a table 🔌

Deep inside every computer, tiny **logic gates** make decisions using just two values: **1** for true and **0** for false. The gates combine inputs with the operators **AND**, **OR** and **NOT**. A **truth table** lays out the output for every possible combination of inputs, so you can see exactly what a logic circuit does.

The logic operators 🔑

Four ideas run through this module:

AND and OR ⚖️

The two operators that combine two inputs are AND and OR. Both take inputs of 1 for true or 0 for false.

Match each operator 🔗

  • AND
  • OR
  • NOT
  • Truth table
  • Outputs 1 only when both inputs are 1
  • Outputs 1 when at least one input is 1
  • Inverts a single input, turning 0 into 1 and 1 into 0
  • Lists the output for every possible combination of inputs

Fill the AND table ✳️

An interactive activity.

Read the OR table 🎯

In an OR truth table, what is the output when A = 0 and B = 1?

  • 1
  • 0
  • 2
  • Both 0 and 1

Logic in words 🧩

A truth table lists the output for every possible _____ of inputs. The AND operator gives 1 only when _____ inputs are 1. The OR operator gives 1 when at _____ one input is 1. The NOT operator _____ its input. To be systematic, list the rows in _____ order.

combination both least inverts binary output either most keeps random

Working systematically 📋

With two inputs there are four rows; with three inputs there are eight. To be sure you list them all, use **binary-count order**: 00, 01, 10, 11 for two inputs, and 000 up to 111 for three. For a combined expression like (A AND B) OR C, add an **intermediate column** for A AND B first, then work out the final column from it.

Count in binary 🔢

An interactive activity.

Fill the combined table 🧮

An interactive activity.

Read the NOT gate 🚫

The NOT operator inverts its input. What is the output of NOT 1?

  • 0
  • 1
  • 2
  • It stays the same

Spot the true statements 🖍️

An interactive activity.

Build the expression 🧭

An interactive activity.

Build a truth table ✍️

An interactive activity.