A·B + C — truth table
intro8 rows over A, B, C
Answer
8 rows, 5 true (1, 3, 5, 6, 7)
Why this example is worth doing
The default example, and the one that establishes how the table is laid out: variables in alphabetical order, A as the most significant bit, rows counting up in binary from 000 so that the row index is the minterm number. That convention is not universal — some textbooks count down, and some put the last variable first — so the page states it explicitly and offers a column-order control. The table also carries an intermediate column for A·B, because the marks in an exam are usually for the intermediate columns.
Try your own input in the Truth table generator. Turn an expression into a full truth table, with a column for every sub-expression.
How the answer is reached
Truth table
| # | A | B | C | A · B + C |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 |
| 1 | 0 | 0 | 1 | 1 |
| 2 | 0 | 1 | 0 | 0 |
| 3 | 0 | 1 | 1 | 1 |
| 4 | 1 | 0 | 0 | 0 |
| 5 | 1 | 0 | 1 | 1 |
| 6 | 1 | 1 | 0 | 1 |
| 7 | 1 | 1 | 1 | 1 |