There are 6 recognisable ways a child goes wrong here — distinct patterns, not carelessness.
Each one below is a mistake our question bank was built to expose, written out the way you would actually hear it said out loud at home.
Knowing which one you are looking at is the whole job. "Check your answer" does not help a child who is confidently applying the wrong rule.
What you might hearThat one is a rectangle, but this tilted square is not.
Child agrees a normal square is a rectangle. But child says a tilted or huge square is not.
Child ties the rule to one shape they pictured. They do not see it covers every square.
Words rarely shift this one. It needs something to look at — a picture, a fold, an object on the table — before the explanation lands.
What you might hearA square is a rectangle, but not every single square is.
Child says a square is a rectangle. But child rejects that all squares are rectangles.
Child treats the word all as too strong. They allow exceptions to a rule that has none.
This one responds to correction in the moment — the idea is there, the rule being applied is not.
What you might hearAll squares are rectangles, so all rectangles are squares too.
Child knows all squares are rectangles. Child flips it and says all rectangles are squares.
Child thinks the rule works both ways. They do not see direction in the all claim.
Words rarely shift this one. It needs something to look at — a picture, a fold, an object on the table — before the explanation lands.
What you might hearA square does not have four right angles. That is a rectangle thing.
Child thinks a square stops having rectangle attributes once it is named a square.
Child sees the two names as separate boxes. Each name owns its own attributes only.
This one responds to correction in the moment — the idea is there, the rule being applied is not.
What you might hearIt is just a square. It is not a quadrilateral.
Child says a square is just a square, not also a quadrilateral with four sides.
Child uses only the closest name. They skip the broader categories above it.
This one responds to correction in the moment — the idea is there, the rule being applied is not.
What you might hearEvery rectangle has four equal sides, just like a square.
Child thinks a rectangle has all a square's attributes, like four equal sides.
Child reverses the direction. They give parent shapes the child's special attributes.
This one responds to correction in the moment — the idea is there, the rule being applied is not.
For each mistake above, Algo School gives you the words to say next — the specific response that corrects the thinking instead of just marking the answer wrong, plus practice aimed at that exact error.
See your child's own results — start freeJames double-checks an inheritance fact. Every trapezoid is also a ___?
Answer A — quadrilateral
Generated by shape-classify-5, a deterministic question engine — not written by an AI, and verified before any child sees it.
Look at what they SAY, not just what they wrote. Each mistake above includes the phrasing a parent typically hears — that sentence is usually the giveaway. In Algo School, the tutor recognises these patterns while your child is working and adapts the session around the one it sees.
Yes. We track 6 distinct approved mistake patterns for this concept, each one written up because it recurs — not because it is unusual. A child making one of them is doing something systematic, which is far easier to fix than random errors.
Respond to the thinking, not the answer. Algo School gives parents the specific wording for each mistake, then generates practice targeted at that error and shows you whether it actually cleared.
They are part of the same content library that drives practice: each one is reviewed and approved before it is used, and the Geometry questions on this site are checked by an automated verification pass before a child is ever served them.
See the full curriculum map — every Common Core concept we cover, the verified question count, and what a child at this level should know.
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See your child's own results — start free