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The 10 Most Common Math Mistakes Students Make on the Upper Level ISEE

The Upper Level ISEE is known for challenging even the strongest math students. It’s fast-paced, conceptual, and intentionally designed to test how well students can think under pressure—not just how well they can follow school-style procedures. Because of this, students often fall into predictable traps.

Math Mistakes Students Make on the Upper Level ISEE

Here are the 10 most common math mistakes we see during ISEE prep, along with short explanations of why they happen and how to begin fixing them.


1. Rushing Through Multi-Step Problems

Many ISEE questions require several steps, but under time pressure, students often jump straight to calculations without organizing the work first.Even students who understand the concept make small errors—dropping a negative sign, forgetting a final step, or misreading a coefficient.Most errors on the Upper Level don’t come from not knowing the math—they come from rushing it.


2. Not Reading the Entire Question

ISEE questions often include “trap phrasing.”They may ask for:

  • “the difference,” not the total

  • “how many more,” not “how many”

  • “which statement is NOT true”

  • “the value of x + y,” not just x


Strong students lose points simply because they answered the question they thought they saw, not the one that was written.


3. Treating Word Problems Like Equations to Memorize

The Upper Level ISEE rewards interpretation, not formula-driven thinking. Students often look for a pattern or memorize a shortcut instead of translating the words carefully.But word problems require:

  • building equations from scratch

  • identifying relationships

  • spotting key details


Students who rush this step often get stuck—not because the math is hard, but because the setup wasn’t clear.


4. Gaps in Fraction, Ratio, and Proportion Skills

These concepts appear everywhere: algebra, geometry, probability, and mixed multi-step questions.Students who avoid fractions or rely heavily on calculators at school struggle the most.The ISEE expects students to:

  • simplify quickly

  • convert between forms

  • solve proportional relationships

  • compare ratios logically


Weakness in fractions creates a domino effect across the entire exam.


5. Not Knowing Essential Formulas Cold

The ISEE does not provide a formula sheet.Students must have full command of:

  • area formulas

  • volume formulas

  • exponent rules

  • slope and linear equations

  • triangle properties

  • coordinate geometry basics


Guessing or “trying to remember” costs both time and accuracy.


6. Mismanaging Time

The math sections move fast—far faster than typical school tests. Students often:

  • spend too long on one hard problem

  • speed through too quickly and miss easy points

  • panic when they realize they are behind

  • lose accuracy in the final third of the section


Even strong students need pacing strategies, not just content review.


7. Difficulty Without a Calculator

Upper Level math in school often allows calculators for fractions, roots, and large numbers. The ISEE does not.Students unused to pencil-and-paper computation may freeze or waste unnecessary time, especially with:

  • long division

  • fraction operations

  • exponents

  • estimating square roots


Calculator-free practice significantly boosts confidence.


8. Not Checking Whether an Answer Makes Sense

Students sometimes produce:

  • negative lengths

  • probabilities greater than 1

  • volumes that are too small

  • answers that contradict the diagram


The ISEE rewards students who pause for one second to check whether the result is even possible.


9. Not Showing Work (Mentally “Doing It in Their Head”)

When students skip writing steps, they lose:

  • the ability to track logic

  • clarity on where an error happened

  • structure in multi-step questions


Writing work doesn’t slow students down—in fact, it keeps them from losing points on otherwise correct reasoning.


10. Test Anxiety and Overthinking

Some students understand every concept but freeze when the clock starts. Others second-guess themselves, change answers, or panic when they see an unfamiliar-looking question.The remedy isn't more worksheets—it’s exposure to real test conditions.Timed practice, full-length tests, and repetition transform this exam from something “scary” into something predictable.


The Upper Level ISEE is less about memorizing math and more about applying thinking skills under pressure. The good news? All ten of these mistakes are fixable with the right preparation plan.When students learn strategies, build foundational skills, and practice consistently, their scores improve—often dramatically.


 
 
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