Solve add-to, start-unknown word problems within 20

G1.OA.11Grade 1OperationsSource mission: Change Stories

Given an amount added and a resulting total, finds the original starting amount.

Progress & proof summary

LifecycleNot started

Evidence progress0 of 2 pieces collected

Current predictionNo prediction yet

Next reviewNot scheduled

Mastery projection: Not available yetWhat does this mean?

1.OA.A.1 1.OA.D.8

cannot start modeling because the first quantity is unknown — the hardest add-to type

These evidence lanes define what would count toward this atom.

EvidencePerformanceStatusNext step

Apply the ideaUse the idea in a new situation Not startedCollect one observation

Represent itShow the idea with a model or notation Not startedCollect one observation

No evidence recorded yet

The first response record for this atom will appear here.

Recommended next step

Use one focused task to begin collecting evidence for this atom.

Apply the idea

Given an amount added and a resulting total, finds the original starting amount.

Estimated time: ~5 min