There are 3 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 hear9 is bigger than 4 so 3/9 is more.
Says 3/9 > 3/4 because 9 > 4.
Applies whole number intuition to denominators.
This one usually gives way to a comparison with something your child already knows, rather than to a restatement of the rule.
What you might hearThey both have 8 on the bottom, so they're the same.
Asked which is bigger, 3/8 or 5/8, the child says they are equal (or just guesses) because both have 8 on the bottom. They never compare the 3 and the 5 — the numbers that actually decide which fraction is bigger.
The child notices the matching bottom numbers and treats same-denominator fractions as 'the same kind,' so they think the comparison is already done. They have not yet learned that when the pieces are the same size (same denominator), the fraction with more pieces (the bigger numerator) is the bigger one.
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 hearThis shaded part is bigger, so one-fourth is bigger.
When the whole shapes in a picture are different sizes, the child picks the fraction with the larger-looking shaded part. For example, they say 1/4 is greater than 1/3 because the fourth is drawn on a bigger bar.
The child sees a fraction as a piece of a picture, not as a part of one equal whole. They have not learned that the wholes must match before a fraction comparison is fair.
Words rarely shift this one. It needs something to look at — a picture, a fold, an object on the table — before the explanation lands.
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 freeNoor has two fractions: 1/3 and 2/3. Which one is larger? The bars show each fraction shaded.
Answer A — 2/3
Generated by fraction-comparison-3, 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 3 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 Number and Operations — Fractions 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