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←MathGrade 1Place Value

Knowledge atom

Justify a within-100 addition with a model, drawing, or strategy

G1.NBT.21Grade 1Place ValueSource mission: Add Two-Digit Numbers

Explains and defends the reasoning used for a two-digit addition, connecting a written method to a concrete or drawn representation.

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Progress & proof summary

LifecycleNot started
Evidence progress0 of 2 pieces collected
0%
Current predictionNo prediction yet
Why?
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Mastery projection: Not available yetWhat does this mean?

Standards alignment

1.NBT.C.4

Prerequisites

Common misconceptions

  • describes the steps of a procedure without reference to quantity

Required evidence

These evidence lanes define what would count toward this atom.

i
EvidencePerformanceStatusNext step
Explain the ideaDescribe why the response works Not startedCollect one observation
Represent itShow the idea with a model or notation Not startedCollect one observation

Recent evidence

No evidence recorded yet

The first response record for this atom will appear here.

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Explain the idea

Explains and defends the reasoning used for a two-digit addition, connecting a written method to a concrete or drawn representation.

Estimated time: ~5 min

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