Decimal Number Line Lab
Decimals are positions on the number line. Zoom in to see how 0.3, 0.33, and 0.37 sit apart, settle once and for all whether 0.409 or 0.41 is bigger — and walk the line by adding.
Zoomable number line
Walk the line
The dark walker starts at 2.4. Each step right adds 0.35. Walker is now at 2.4.
Challenges
1. Plot 0.3, 0.33, and 0.37 — which two are closest?
Zoom to 0.30 – 0.38 and look at the gaps.
2. Predict: is 0.409 or 0.41 bigger?
Decide first, then zoom to 0.405 – 0.415 and check — were you right?
3. Walk: start at 2.4, add 0.35 three times
Use the “Step right” button (or add by hand), then type where the walker lands.
Takeaway
Adding is walking right; subtracting is walking left. Zooming in never changes the order — 0.41 stays bigger than 0.409 no matter how close you look, because 0.410 > 0.409 in the thousandths column.