Thinking Summary · 1
Mastered[object Object]
[Discovery] Place 67 on the number line between 60 and 70.
1
Active Step[Discovery] Place 67 on the number line between 60 and 70.
Number Line
Place the marker on 67.
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60 ⟵ ⟶ 70
Welcome to "Star Rounder", a Grade 3 Rounding to the Nearest Ten or Hundred mission at the Explorer core practice level, staged in a space scenario. The mission opens with a hands-on prompt: "Place 67 on the number line between 60 and 70." Students work with the numbers 67, 60, 70 and reach a final answer of 70 across 3 guided steps.
Behind the story, this lesson builds rounding to the nearest ten or hundred understanding aligned to CCSS 3.NBT.A.1. The key strategy is: Halfway rule: if the gap ≥ 5, round UP.
A common misconception this page surfaces is: At the exact halfway (e.g. 35), rounding randomly. Convention: 5 or more rounds up. 35 → 40, not 30. The adaptive Socratic hints move from a small nudge to a fuller strategy, keeping the reasoning visible for students, parents, and teachers.
Grade 3 · Rounding to the Nearest Ten or Hundred
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] Place 67 on the number line between 60 and 70.
1
Active StepPlace the marker on 67.
3rd Grade Rounding explorer-2 representative practice page for students who need a crawlable, worked entry point into the topic without exposing every near-duplicate long-tail mission.
This explorer · core practice mission uses a number line to move from the story to a precise rounding idea. Work through the prompts in order: notice the structure first, name the quantities, then check whether the final answer fits the original situation.
Common wrong turn: 60 is the lower neighbor. 67 is past it.
Common wrong turn: 67 is closer to 70 (gap = 3) than to 60 (gap = 7).
Common wrong turn: 60 is BELOW 67, not above.
In 3rd Grade Rounding, students need to connect the story, the model, and the symbolic answer. The core move here is: Halfway rule: if the gap ≥ 5, round UP. A useful check is to ask whether the answer avoids this pitfall: At the exact halfway (e.g. 35), rounding randomly. Convention: 5 or more rounds up. 35 → 40, not 30.