Welcome to "Fuel Tank Reader", a Grade 3 Mass and Liquid Volume mission at the Explorer core practice level, staged in a space scenario. The mission opens with a hands-on prompt: "The scale runs from 0 to 500 g in steps of 50. Mark the needle at 250 g." Students work with the numbers 0, 500, 50 and reach a final answer of 450 across 3 guided steps.
Behind the story, this lesson builds mass and liquid volume understanding aligned to CCSS 3.MD.A.2. The key strategy is: Ticks × 50 = reading.
A common misconception this page surfaces is: Treating g and kg as interchangeable without converting. 1 kg = 1000 g. You can only add/subtract once units match — convert first. The adaptive Socratic hints move from a small nudge to a fuller strategy, keeping the reasoning visible for students, parents, and teachers.
Grade 3 · Mass and Liquid Volume
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] The scale runs from 0 to 500 g in steps of 50. Mark the needle at 250 g.
1
Active StepPlace the marker on 250.
3rd Grade Mass and Liquid Volume 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 mass and liquid volume 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: That's one tick early. Add another 50.
Common wrong turn: That's the tick COUNT. Multiply by 50 to get g.
Common wrong turn: That subtracts. We need the COMBINED mass.
In 3rd Grade Mass and Liquid Volume, students need to connect the story, the model, and the symbolic answer. The core move here is: Ticks × 50 = reading. A useful check is to ask whether the answer avoids this pitfall: Treating g and kg as interchangeable without converting. 1 kg = 1000 g. You can only add/subtract once units match — convert first.
Everything you need to know about the Socratic experience.
The scale runs from 0 to 500 g in steps of 50. Mark the needle at 250 g. Hint: Each tick equals 50 g. Count ticks from 0.
A second tank of coolant reads 200 g. Total = ? (in g) If you get stuck, the adaptive hint is: 250 + 200 = ?
Explorer missions hit the core abstraction at typical numeric ranges — this is where conceptual mastery is built. Within Grade 3 Mass and Liquid Volume, expect numbers in the corresponding range.
Treating g and kg as interchangeable without converting. 1 kg = 1000 g. You can only add/subtract once units match — convert first.
Bar Graph (Comparing measured masses naturally produces a bar-graph data set.) Open /grade-3/bargraph to start that topic's missions.
Yes. Every mission, handbook page, and topic hub is mapped to a specific CCSS code (visible in the page header). The curriculum follows the CCSS coherence map: Grade 1 number sense → Grade 3 multiplicative thinking → Grade 6 ratio reasoning, with each grade building strictly on the prior year's foundations.
Inquiry-based learning starts with a question, not a formula — students explore, hypothesize, and verify before being told the rule. In Inquiry AI, every mission opens with a "Discovery" step (manipulate the model), then "Abstraction" (write the equation), then "Reflect" (apply to a new case). The procedure is never given upfront; learners derive it from their own observations.
