A free interactive hundred square
A hundred square arranges one hundred consecutive numbers in ten rows and ten columns. This tool has two layouts: 1–100 and 0–99. Open Explore to mark numbers, compare patterns and hide or reveal squares. Choose Find the missing number for eight untimed challenges on either board. There is no signup, countdown or requirement to drag.
One more across, ten more down
Move right within a row to add one. Move down within a column to add ten. On the 1–100 board, the first row is 1 to 10 and the final row is 91 to 100. On the 0–99 board, rows begin with a multiple of ten: 0, 10, 20 and so on. The layout changes where the tens appear, while the one-more and ten-more relationships stay the same.
Row boundaries matter. Moving right from 10 on the 1–100 chart would leave its row, so the right-arrow control stops there. The Back 10 and Forward 10 buttons move only when that complete step fits. The selected-number panel reports the exact row, column and place value, including one hundred as one hundred, zero tens and zero ones.
Paint numbers and compare patterns
To build the value of a number with separate hundreds, tens and ones, open Place Value Workshop. Its blocks can exchange ten ones for one ten without changing the total.
Choose Blue paint or Amber paint, then tap a square. Using the same paint on that square again removes it. Eraser removes a mark; Inspect selects a number without painting. The selected-number controls let you enter a value, move by one or ten, and apply the current tool with a large button. Clear paint removes manual marks, and Undo paint restores the previous paint state.
The pattern selector adds teal underlines for odd numbers, even numbers, primes or multiples from two to twelve. It keeps your manual paint, so you can mark a prediction and compare it with an overlay. Try painting multiples of three, then viewing multiples of six. Which squares have both paint and an underline? On the zero-start chart, zero is even and is a multiple of every positive whole number; it is not prime. One is not prime either.
Hide numbers conceals the chart labels. Tap a hidden square to reveal it. Show all numbers brings the labels back without clearing paint. Hidden and revealed states belong to Explore; the missing-number activity always presents its own chart with exactly one concealed value.
Missing-number practice with time to think
Locate the question mark by its row and column. Follow the visible neighbours and choose one of four numbers. Check my answer gives feedback; an incorrect choice stays on the same challenge so you can try again. A correct answer waits for Next challenge. Complete eight questions to earn that board’s sticker in your sticker book.
Find it with help gives a written route from the first number in the row to the concealed value. It reveals the answer. Completion stickers recognise supported practice, rather than measuring independent mastery. The activities practise selected number-chart skills; they are not a complete maths assessment.
Phone, keyboard and saved-work controls
The chart keeps all ten columns on phones. Larger controls below it let you select a number and use the current tool without tapping a small square. With a keyboard, Tab enters the exploration chart once. Arrow keys move within rows and columns; Home and End select the first and last square in the current row. Control plus Home or End goes to the chart’s endpoints. Enter or Space uses the selected tool. Moving focus does not paint.
Your two exploration boards and two practice routes save separately in this browser. Change activity keeps your work. Return to the page and choose the same activity and board to continue. If browser storage is unavailable, a message explains that progress lasts only while the page stays open. Settings opens the existing grown-up controls.
For a different view of number position, try Number Line Workshop. Connect the chart with addition practice, or explore equal groups in times-table games. For smaller quantities, start with untimed dot counting.
Make counter pairs and practise sorting in Odd and Even Workshop: three number ranges and eighteen saved boards.