About the Hundreds Chart
A hundreds chart earns its spot on the wall because so many number-sense ideas live on the same grid: skip-counting patterns, even and odd columns, the way adding ten just moves a number straight down a row. This tool keeps all of that on one interactive 1-100 grid, with a 0-99 numbering option for classrooms that teach the chart that way, and lets you turn any skip-counting pattern into a live highlight instead of a worksheet you have to redraw by hand.
Past the highlighting, the chart doubles as a quick fill-in worksheet generator. Blank out every number, blank out everything except the multiples you're highlighting, or click individual cells yourself to mark them up for a custom pattern, then print exactly what's on screen.
How to use it in your classroom
- Choose 1-100 or 0-99 numbering to match how your classroom's chart is labeled.
- Turn on "Highlight skip-counting," pick a step of 2, 3, 5, 10, or a custom number, and set a start offset — the matching cells highlight instantly as you adjust either setting.
- Switch "Hide numbers" to blank the whole grid, blank only the numbers that aren't part of your highlighted pattern, or generate a random percentage to hide by clicking Apply.
- Click any cell directly to mark it by hand, independent of the automatic highlight — useful for a pattern the built-in step options don't cover. Use Clear marks to reset just the manual marks.
- Click Print chart to print just the grid, with the controls panel left out of the printed page.
Tips from the classroom
- Project the chart and change the step live while counting aloud as a class — watching the highlighted cells jump from 5 to 10 to 15 reinforces the pattern better than pointing at a static poster.
- Use "hide non-multiples" with a step of 10 as a quick first-grade check: if a student can fill in just the multiples of ten, you've confirmed they see the column pattern.
- The random hide percentage is a fast way to make a fresh fill-in sheet for early finishers — click Apply again for a new random set without changing anything else.
- Manual marking is handy for patterns the step options don't cover, like marking every prime number or every number with a digit sum of seven, by hand, cell by cell.
- Switch to 0-99 numbering before teaching place value with tens and ones, since some curricula start the chart at zero so the tens digit lines up cleanly with the row number.
Frequently asked questions
Does the skip-counting highlight update automatically, or do I need to click a button?
It updates live. As soon as highlighting is turned on, changing the step or the start offset instantly recalculates which cells are highlighted — there's no apply button for that part.
What's the difference between hiding non-multiples and the random hide option?
Hiding non-multiples is deterministic: it always blanks exactly the numbers that don't match your current step and offset, so it's predictable and safe to reload. The random option lets you pick a percentage to hide and only generates that random set when you click Apply, so it never changes on its own.
Can I mark cells by hand and use the skip-counting highlight at the same time?
Yes. Manual marks and the automatic skip-counting highlight are two separate layers — clicking a cell toggles your own mark on top of whatever the highlight settings are already showing.
What prints when I click Print chart?
Just the number grid. The settings panel on the side is hidden automatically so the printed page only shows the chart itself, sized to fit cleanly on one page.