---
title: "Multiplication Tables"
id: 57025
type: "computer_media"
slug: "multiplication-tables"
url: "http://localhost/computer_media/multiplication-tables/"
markdown_url: "http://localhost/computer_media/multiplication-tables.md"
published_at: "2024-10-02T07:46:57+00:00"
modified_at: "2026-03-30T21:20:02+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2024/10/49_Mul.png"
excerpt: "A compact multiplication table printer that quizzes you on any times table up to ×10, looping until you type \"NO\" to quit."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
model:
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
genre:
  - name: "Education"
    slug: "education"
    taxonomy: "genre"
    url: "http://localhost/type/education/"
  - name: "Mathematics"
    slug: "mathematics"
    taxonomy: "genre"
    url: "http://localhost/type/mathematics/"
media_contents:
  - id: 56732
    title: "Timex Sinclair Public Domain Library Tape 1001"
    type: "computer_media"
    url: "http://localhost/computer_media/timex-sinclair-public-domain-library-tape-1001/"
media_type: "Program"
mediadate: "198x"
images:
  - url: "http://localhost/wp-content/uploads/2024/10/49_Mul.png"
media_type_tags: "Education, Mathematics"
---

# Multiplication Tables

This program displays multiplication tables for a user-chosen number, printing the series from 1× to 10× in a formatted layout. After displaying the table, it prompts the user to try another and loops back unless “NO” is entered. The condition `IF NOT A$=”NO”` is a characteristic Sinclair BASIC idiom where `NOT` applies to the entire string comparison, returning 1 (true) if the strings are not equal. The double commas in line 12 (`PRINT ,,J`) use comma column-tabbing to position output across the screen. The program includes a SAVE command with an auto-run flag embedded in the filename.

***

## Program Analysis

### Program Structure

The program is divided into three logical phases: an introduction/input screen (lines 1–3), the table display loop (lines 10–13), and a replay prompt with conditional branching (lines 14–21). Line 30 halts execution cleanly with `STOP`, while lines 40 and 45 are utility lines for saving and auto-running.

1. **Introduction (lines 1–3):** Titles the program and solicits the multiplier via `INPUT A`.
2. **Table display (lines 10–13):** A `FOR` loop from 1 to 10 prints each multiplication result.
3. **Replay logic (lines 14–21):** Prompts for another try, branching back to line 2 unless the user types “NO”.

### Key BASIC Idioms

Line 12 uses `PRINT ,,J;" X ";A;" = ";A*J`. The two leading commas advance the print position by two tab columns before printing the expression, giving the output a centred appearance on a 32-column display. This is a common Sinclair BASIC spacing trick.

Line 19 uses `IF NOT A$="NO" THEN GOTO 2`. In Sinclair BASIC, `NOT` has lower precedence than the relational operator, so this evaluates as `IF NOT (A$="NO")` — i.e., loop back unless the user typed exactly “NO”. This idiom is idiomatic but can surprise programmers expecting C-style logical-NOT behaviour.

Line 2 uses a single `PRINT` statement with a comma-separated string to print on two consecutive lines, a standard Sinclair multi-line print shorthand.

### Program Flow Table

| Lines | Purpose |
| --- | --- |
| 1–3 | Title display and initial multiplier input |
| 10–13 | `FOR` loop printing the ×1 to ×10 table |
| 14–17 | Prompt and input for replay decision |
| 18–19 | `CLS` and conditional branch back to line 2 |
| 21 | Farewell message |
| 30 | `STOP` |
| 40 | `SAVE` with auto-run flag |
| 45 | `RUN` (executed if program is loaded without auto-run) |

### Notable Techniques

- The loop variable is `J` (line 11), while the multiplier is `A` (line 3), keeping variable names distinct and avoiding shadowing.
- The replay loop reuses the `INPUT A$` at line 17 without re-displaying the full title (line 1), branching directly to line 2 to re-prompt for a new table number — a minor UX economy.
- Line 21 uses `PRINT AT 21,0;,` with a trailing comma before the string, which tabs to the next print zone before outputting the farewell, centering it roughly on screen.

### Bugs and Anomalies

- The replay check is case-sensitive: entering “no” or “No” will cause the program to loop back rather than exit, which may surprise users.
- There is no validation of the `INPUT A` value — entering 0 or a non-numeric value will either produce trivial output or cause an error.
- Line 14 uses `PRINT AT 20,0`, which may overlap table output if 10 rows of data have scrolled or if the screen has not been cleared since the previous iteration; however, the `CLS` at line 10 ensures a clean display at the start of each table.

## Source Code

```
   1 PRINT AT 2,8;"MULTIPLICATION TABLES"
   2 PRINT AT 6,2;"WHICH TIMES TABLE WOULD YOU","LIKE ME TO PRINT?"
   3 INPUT A
  10 CLS 
  11 FOR J=1 TO 10
  12 PRINT ,,J;" X ";A;" = ";A*J
  13 NEXT J
  14 PRINT AT 20,0;"DO YOU WANT ANOTHER TRY?"
  17 INPUT A$
  18 CLS 
  19 IF NOT A$="NO" THEN GOTO 2
  21 PRINT AT 21,8;,"OK. BYE FOR NOW."
  30 STOP 
  40 SAVE "1004%9"
  45 RUN
```