How to use concentration grids in class
A concentration grid is a sheet of numbers in random order. Students find them in order, starting from the first number, as fast as they can. It takes a few minutes, needs no preparation, and works on a screen or on paper, which makes it an easy routine to fit around a lesson.
Pick a grid size
- 10 numbers (0–9) for the youngest students, or anyone trying it for the first time.
- 25 numbers (00–24) is a good everyday size: long enough to need focus, short enough to finish in a few minutes.
- 50 or 100 numbers for older students who want a longer challenge. The 100-number grid (00–99) is the classic full grid.
- A 5×5 Schulte table (1–25) if your students already know the format. See What is a Schulte table?.
When in doubt, start smaller than you think. A grid a student can finish is more motivating than one they abandon halfway.
Three routines that work
Warm-up. Open the lesson with one round: a 25-number grid, or a 30-second sprint where students find as many numbers as they can. It gives everyone the same calm, focused start, and latecomers can join the next round.
Brain break. Between two longer tasks, one round is a short reset that still asks for attention, unlike a free-for-all break that can be hard to bring back.
Weekly challenge. Pick a day, keep the grid size the same, and have students write down their time each week. Over a term, the record of their own times is the most convincing evidence they will see that practice pays off.
Screens or paper
On devices, students open the online grids, pick a size and press Start. The grid stays blurred until they start, the timer runs on its own, and wrong taps are counted. Each finished run is saved to the history page, but only in that browser, so on shared Chromebooks or tablets the times of different students will mix. In that case, have students write their time on paper too.
On paper, print a set of grids. Every page is generated fresh, so no two students get the same sheet, and each page has lines for name, date and time. Students can time each other in pairs, or you can run one clock for the whole room and have them write down the time showing when they finish.
On a projector, you can play one grid together. Put a grid on the board, and let students take turns calling out where the next number is. It is a good way to introduce the activity before anyone plays alone.
Keep it about personal bests
Some students love a race; others freeze when they are compared with classmates. The safest framing is that every student competes only with their own last time. Avoid posting a class leaderboard, and celebrate improvements instead of the fastest time in the room.
If the running clock makes a student anxious, they can hide it: set Timer to Hide before starting. The time is still recorded at the end.
A quick start for tomorrow
- Print one page of 25-number grids per student, or check that devices can open the site.
- Show a grid on the board and find the first few numbers together.
- Run one timed round. Students write their time on the sheet.
- Next time, run the same size again and ask who beat their own time.