Ratio Generator
Generates a random ratio in the form a:b, with each part independently drawn from 1 to 20 — not automatically simplified.
What this generator does
Produces a ratio in the a : b form, for maths practice on scaling, proportion and simplification.
How to use this tool
- Press generate for a random ratio.
Worked examples
- Format
- 3 : 8
Common use cases
- Ratio-recognition practice
- Placeholder ratio data
- A starting point for a ratio simplification exercise
How this generator works
Two whole numbers are drawn independently from 1 to 20 and written as a : b, without being simplified. Leaving them unsimplified is the point: 6 : 8 and 3 : 4 describe the same proportion, and a ratio drawn already in lowest terms would never give anyone the chance to notice that. Because the parts are drawn independently, roughly a third of the pairs share a common factor, so simplification practice has something to bite on more often than not.
Limitations and good to know
- The two parts are independent, so 4 : 4 and other equal pairs come up — a ratio of one to one is a legitimate ratio, not a fault.
- Neither part is ever zero, because a ratio with a zero part cannot be simplified or scaled and is not a useful exercise.
- Both parts stay within 1 to 20. Larger ratios exist, but past twenty the arithmetic stops being mental and the exercise becomes a different one.