Zoom in. Find the nearest.

SparkClass

Drag the point. Compare both distances.

CCSS 3.NBT.A.1
Live Zoomed Number Line
Nearest 10
Zoomed rounding number line 346 is between 340 and 350. It is 6 units from 340 and 4 units from 350, so 346 rounds to 350.
01

350 is closer. 346 is 4 units from 350, but 6 units from 340.

346 Rounds ToNearest 10 → 350

Make “nearest” visible

Start with distance, not a digit trick. The zoomed line keeps both candidate anchors and the halfway point visible.

1

Predict before revealing

Hide the answer and ask students to pick an anchor. Keep the distances visible: students should compare 46 with 54, for example, rather than guess from a rule.

2

Cross an anchor slowly

Use the slider around 99–101 or 349–351. When the number crosses an exact 10 or 100, the window rebuilds around the next pair. The small locator shows where that window sits from 0 to 1,000.

3

Make the tie rule explicit

Try 350 in Nearest 100 mode. Both distances are 50, so neither anchor is closer. This lab uses the common convention that an exact midpoint rounds up to the larger anchor: 350 → 400. Try 725 in Nearest 10 mode for another tie.

4

Check the edges

Compare 49 and 51 in Nearest 100 mode, then try 999. Also test 0 and 1,000. Exact anchors have distance 0 and stay unchanged; rounding never goes beyond the 0–1,000 range.

CCSS 3.NBT.A.1 alignment: use place value understanding to round whole numbers to the nearest 10 or 100. This manipulative emphasizes the number-line meaning of “nearest” and the convention for exact midpoints.