1 to 20

About 1–20

How many numbers

20

Chance of each

5%

Average draw

10.5

Primes in it

8

There are 20 numbers from 1 to 20, so each one has a 5% chance and the average draw settles at 10.5. 10 of them are even and 8 are prime — which is why a “random-looking” draw is no less likely than a round one.

Other ranges

Each one on its own page

• Dice roller

  One die or six, from d4 to d100, drawn as the solid it is.

• Coin flip

  Heads or tails, with a running tally of the flips so far.

• Random letter

  A letter of the alphabet — all of them, or only vowels.

The rest of the kit

• Name wheel

  Spin to pick a pupil. Nobody is picked twice until everyone has had a turn.

• Random groups

  Split the class into even groups in one click, by number of groups or by size.

• Classroom timer

  A countdown the back row can read, with a bar that turns amber, then red.

• Stopwatch

  Start, lap, stop. Laps with splits, fastest and slowest marked.

• Focus timer

  Work and break rounds that run by themselves, 25 and 5 or your own.