Random number generator for the classroom
A number machine for the projector: hold to roll the reels, let go and they lock digit by digit. A class board fills in as numbers are drawn, with place value, line-up and guess-my-number modes. No ads, nothing sent anywhere.
The board: tap a number to mark it away today
How to use it
- Tap a quick range (1–10 up to 1–100, or Bingo 1–75) or type the lowest and highest numbers. Choose odd, even, multiples or counting by, and how many to pick.
- Hold Space or the Hold to roll button: the reels whirl until you let go, then lock one digit at a time. The numbers were drawn first by your browser's secure random generator; the reels only show them.
- Tap a number on the board to mark it away today, or type numbers to leave out. Switch to Digits, Line up or Guess my number with the tabs or the keys 1 to 4.
Ideas for class
- Give each student a number for the year, set the range to your class size and tap anyone away today on the board. Each child sees their own tile light up when they are picked.
- Hold the button and let the class count down “3, 2, 1” before you let go: the reels land on the cue.
- Digits mode, Reveal: the digits uncover one place at a time from the left, each in its place colour. Ask the class to say the number before the last digit lands, then read its name and expanded form.
- Digits mode, Digit draw: each child writes every digit in a box of their choice. Who made the greatest number? The screen shows the greatest and smallest possible.
- Guess my number from 1 to 100: the class calls guesses and the arrow says higher or lower. Seven guesses are always enough; can they find out why?
- Line up gives the whole class a random order with 1st, 2nd, 3rd beside each number, for presentations or turns. Copy it into your plan.
- Choose Multiples of 6 for times-table practice, or Count by 25 from 0 to 1,000 for skip counting, and ask for the fact behind each number.
- Run bingo: tap Bingo 1–75 for the B-I-N-G-O letters and a called board, switch on Read each number aloud, and let it call automatically every few seconds.
Related
Questions
Is each number equally likely, even with the reels?
Yes. The numbers are drawn first with your browser's secure random generator, with no bias for any number, and only then do the reels start to whirl. How long you hold the button changes the show, never the number. Odd, even and multiples rules draw evenly from the numbers they allow.
How do I leave out a student who is away?
Tap their number on the board: it is hatched and never drawn today, and comes back at midnight. For numbers you always skip, type them in Leave out, like 7, 12, 20-22. The board shows for ranges of up to 100 numbers.
How does “No repeats” work?
It remembers every number already drawn and never draws it again until all have been used, then it tells you. Reset puts every number back. Untick it to allow the same number to come up again.
How big can the range be?
From minus one million to one million, and the rules work on the whole range without building a list. Line up shows up to 500 numbers, and the board up to 100.
What does Digits mode do?
It draws a number of one to seven digits for place value. Reveal uncovers one place at a time and then shows the number in words and in expanded form (400 + 10 + 2). Digit draw gives one digit at a time for a make-the-greatest-number game.
Can it read the numbers aloud?
Yes. Press S or Say it, or tick Read each number aloud. It uses your browser's own voice, so nothing is sent anywhere. Sounds are made by your browser too; press M to mute.
Can I share my setup?
Yes. “Copy a link to this setup” puts the range and settings after the # sign, which browsers never send to any server. Numbers marked away are not included.
Nothing you do here is sent to us. Names, lists and settings stay in this browser. No sign-in, no ads.