Knowledge atom
Find the unknown in a − ☐ = c
Determines the missing subtrahend in a subtraction equation.
Start practiceProgress & proof summary
LifecycleNot started
Evidence progress0 of 2 pieces collected
0%Current predictionNo prediction yet
Why?Next reviewNot scheduled
Mastery projection: Not available yetWhat does this mean?
Standards alignment
1.OA.D.8
Prerequisites
Common misconceptions
- adds the two visible numbers (answers 23 for 14 − ☐ = 9)
- treats the box as the answer slot and writes the result of any computation there without reading the unknown's role
Required evidence
These evidence lanes define what would count toward this atom.
EvidencePerformanceStatusNext step
Show the stepsCarry out the procedure accurately 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.