Definition
Justification
A justification is a mathematical reason showing why an answer, step, or claim is valid.
What it means
An answer tells what you got. A justification tells why it works. Point to a definition, pattern, diagram, calculation, property, or known fact, then connect it to the claim instead of asking the reader to trust a guess.
Remember it
Do not stop at “what”; give the mathematical “why.”
Example
“34 is even” is justified by splitting 34 objects into 17 pairs with none left over. The equal pairing shows why the claim is true.
Watch for
“34 is even because I know it is” repeats confidence but gives no mathematical reason.
Common mix-up
A justification is evidence and reasoning, not a teacher’s authority or a longer restatement of the answer.
Exact meaning
A justification is a mathematical reason, representation, calculation, definition, property, or connected explanation that shows why an answer, step, or claim is valid. The amount of detail needed depends on the claim.