ISEE Quantitative Comparison Strategy: How to Compare Column A and Column B

ISEE quantitative comparisons confuse most students the first time they see the Column A vs Column B layout, but the format is actually one of the easiest places on the test to bank quick points. This guide breaks down the four answer choices, the simplify and plug-in techniques, and the three rules for choosing (D) — so you can move through 14 to 17 of these questions in under 30 seconds each.

What ISEE Quantitative Comparison Questions Are

ISEE quantitative comparisons sit inside the broader Quantitative Reasoning section, which is the second of the four scored ISEE sections. On the Middle Level and Upper Level tests, the section gives you 37 questions to finish in 35 minutes — and roughly 14 to 17 of those questions are quantitative comparisons rather than traditional word problems. No calculator is allowed.

The Column A vs Column B format

A quantitative comparison shows you two quantities side by side: one labeled Column A and one labeled Column B. Sometimes there is a constraint listed above the columns, like "x > 0" or "a > b > c > d." Your job is not to compute either column to a final number — your job is to decide how the two columns relate. That single shift in mindset, from solving to comparing, is what unlocks fast points in this section.

Which ISEE levels include them

Quantitative comparisons appear only on the Middle Level (grades 7–8 entry) and Upper Level (grades 9–12 entry) ISEE. The Lower Level Quantitative Reasoning section is made entirely of word problems, so if you are taking the Lower Level test you can skip the QC techniques in this guide and focus on word problem strategy instead.

How many you'll see and how much time you have

The full Quantitative Reasoning section runs 35 minutes. Of the 37 questions, 32 are scored and 5 are unscored experimental items — but you cannot tell which is which, so treat every question as if it counts. That works out to about 57 seconds per question on average. Quantitative comparisons can usually be answered faster than word problems if you know the strategy, so a smart pacing plan is to bank time on QCs and spend it on word problems.

Quantitative comparisons appear identically on the Middle and Upper Levels — the format is shared even though content difficulty differs.
DetailMiddle LevelUpper Level
Includes Quantitative Comparisons?YesYes
Total Quantitative Reasoning questions3737
Approximate QC questions14-1714-17
Approximate word problems18-2118-21
Time for the section35 minutes35 minutes
Calculator allowed?NoNo
Bottom line: Recognize the format on sight — two columns to compare, four fixed answer choices, and roughly a minute per question.

The Four Answer Choices and What Each Really Means

Every ISEE quantitative comparison Column A Column B question uses the exact same four answer choices in the exact same order. Memorize them once and you stop reading them on test day, which buys you several seconds on every QC question.

A
The quantity in Column A is greater
Pick this when every valid value or every valid simplification leaves Column A larger than Column B.
B
The quantity in Column B is greater
Pick this when every valid value or every valid simplification leaves Column B larger than Column A.
C
The two quantities are equal
Pick this when both columns simplify to the same expression or evaluate to the same number under every allowed value.
D
The relationship cannot be determined from the information given
Pick this only when at least one column contains a variable AND two valid test values give two different relationships.
The four ISEE QC answer choices never change. Memorize them once and you save reading time on every QC question.
ChoiceMeaningPick When
(A)The quantity in Column A is greaterEvery test value you try shows Column A larger than Column B.
(B)The quantity in Column B is greaterEvery test value you try shows Column B larger than Column A.
(C)The two quantities are equalBoth columns simplify to the same expression or number, no matter what.
(D)The relationship cannot be determinedTwo valid test values give different relationships — and only when at least one column has a variable.

Strategy 1 — Simplify Both Columns First

The first move on almost every quantitative comparison is to simplify. Treat the two columns like an inequality where you do not yet know which way the operator points. Anything you do to keep the columns balanced — adding, subtracting, multiplying or dividing both sides by the same positive number — preserves the unknown relationship between them. The ISEE quantitative comparison strategy here is identical to algebra, just with one twist about variables.

Add or subtract the same value from both sides

If both columns share a term, subtract that term from both sides. The relationship between the columns does not change, but the math gets cleaner. If Column A is x + 7 and Column B is 7 + 2, subtract 7 from both columns — now you are comparing x to 2, which is much easier to think about.

Multiply or divide both sides by the same positive number

Multiplying both columns by a positive constant scales the expressions without changing which one is bigger. The danger is multiplying or dividing by a variable. If the variable could be negative, the inequality flips. If the variable could be zero, the comparison becomes meaningless. Only multiply or divide by a variable when the problem guarantees that variable is positive.

Cancel matching terms before computing

When both columns are sums of similar parts, look for matching pieces you can drop instead of computing. The worked example below uses commutative addition — both columns are the same three numbers in a different order — so the comparison is settled before you do any arithmetic at all.

Worked Example

Setup: Column A: 47 + 88 + 19. Column B: 88 + 19 + 47. Compare the two quantities.

  1. Notice that both columns contain the same three numbers: 47, 88, and 19.
  2. Addition is commutative — order does not change the sum.
  3. Cancel matching terms or recognize that both sums equal 154 without computing.
  4. Confirm: both columns simplify to the same value.
Result: Both columns equal 154, so the answer is (C) — the two quantities are equal. The lesson: spot shared terms before you compute.
Common Mistake: Whatever you do to one column, do the same — and only — to the other. Same operation, same number, same direction.

Strategy 2 — Plug In Smart Test Values

When a quantitative comparison contains a variable, the right move is almost always to plug in concrete numbers for that variable. The trick is picking values that expose the trap. Most students plug in 1, 2, and 3, which often gives the same relationship every time and locks you into a wrong answer. The five-value cycle below catches the cases ISEE QC questions like to exploit.

Start with -1, 0, and 1

These three values are the cheapest stress test you have. Negative one catches sign flips: if your column has a variable raised to an odd power or multiplied by another variable, the negative reverses the result. Zero catches edge cases — anything times zero is zero, division by zero is undefined. One reveals whether multiplication does anything meaningful at all (since multiplying by 1 is the identity).

Then try a fraction between 0 and 1

Squaring a number greater than 1 makes it bigger, but squaring a fraction between 0 and 1 makes it smaller. That single behavior trips up more students than any other plug-in trap. Always include 1/2 in your test values whenever the columns involve squares, square roots, or any power.

Then try a value larger than 5

Some relationships hold for small numbers but break at scale, especially when one column grows linearly and the other grows polynomially. If the small integers all give the same answer, swap in a 6, a 10, or a 100 and re-check. If the relationship still holds, you can commit. If it changes, the answer is (D).

Worked Example

Setup: Given x is a real number. Column A: x squared. Column B: x. Compare the two quantities.

  1. Try x = 2: Column A = 4, Column B = 2, so Column A is greater.
  2. Try x = 1/2: Column A = 1/4, Column B = 1/2, so Column B is greater.
  3. Try x = 0: Column A = 0, Column B = 0, so the two are equal.
  4. Three different test values gave three different relationships.
Result: Because the relationship between Column A and Column B changes depending on the value of x, the answer is (D) — the relationship cannot be determined.
Plugging in only 1, 2, and 3 misses sign and squaring traps. This five-value cycle covers the cases ISEE QC questions tend to exploit.
ValueWhy You Try ItWhat It Catches
-1Tests negative behaviorSign flips when columns multiply by the variable.
0Tests the zero edge caseAnything times zero is zero; division by zero is undefined.
1Tests the multiplicative identityReveals whether multiplying changes the column at all.
1/2 (a fraction between 0 and 1)Tests squaring directionSquaring shrinks fractions in this range — the opposite of what whole numbers do.
A value greater than 5Tests size effectsCatches relationships that hold for small values but break at scale.
Pro Tip: Cycle through -1, 0, 1, a fraction, and one large number. If the relationship is the same all five times, you can commit. If it changes, pick (D).

Strategy 3 — Knowing When to Choose (D)

Answer (D) is the trickiest of the four choices. Picking it too eagerly or refusing to pick it at all are both common ways to lose points. Three rules cut through the confusion.

Rule 1 — (D) is rarely the early-question answer

Quantitative comparison questions are loosely ordered easier-to-harder, and the early questions almost always have a clean computable answer. If you find yourself wanting to pick (D) on the very first QC, double-check your work — odds are you missed a simpler approach.

Rule 2 — (D) is never correct with only numbers

Two fixed numbers always have a definite relationship. If both Column A and Column B contain only specific numerical values — no variables, no unknowns — then the answer must be (A), (B), or (C). Eliminate (D) before you even start computing.

Rule 3 — (D) is correct when more than one relationship is possible

If two valid test values give different relationships between the columns, you've proven the relationship is not fixed. That is what (D) is for. The plug-in cycle from Strategy 2 is your tool for finding this — when -1, 0, 1, or 1/2 give you a different answer than the small positive integers, (D) is locked in.

Warning: Pick (D) because the math demands it, not because the math is hard.

Strategy 4 — Estimate Instead of Calculating

ISEE quantitative comparison questions ask which column is bigger, not what either column equals. That distinction is your opening for estimation. Decimal arithmetic without a calculator burns the clock; rounding and rough size comparisons settle most QCs in seconds.

Compare orders of magnitude first

Before reaching for any pencil work, scan the columns for an obvious size mismatch. If Column A is in the hundreds and Column B is in the tens, you do not need to compute either side — you already have your answer. This is the lazy-but-correct first move on every QC.

Round fractions to 0, 1/2, or 1

Three benchmarks, 0, 1/2, and 1, are enough to settle most fractional comparisons. A fraction with a denominator twice the numerator is about 1/2. A fraction with the numerator close to the denominator is close to 1. Round each fraction to its nearest benchmark, then compare benchmarks.

Use benchmark percentages

Lock in 10%, 25%, 50%, and 100% as anchors. Almost any percentage problem on the ISEE is close enough to one of these to round and compare. 17% of 200 is close to 20% of 200, which is 40 — that's enough to settle a comparison without exact arithmetic, in most cases.

Worked Example

Setup: Column A: 0.49 + 0.51 + 0.49. Column B: 1.6. Compare the two quantities.

  1. Round each Column A term to 0.5 to get a quick mental sum.
  2. 0.5 + 0.5 + 0.5 = 1.5, so Column A is approximately 1.5.
  3. Column B is exactly 1.6, which is bigger than 1.5.
  4. Check whether the small rounding errors could close the gap. Each term rounded by at most 0.01, so the total error is well under 0.05 — not enough to change the answer.
Result: Column B is greater, so the answer is (B). Estimation got you there in seconds without any decimal arithmetic.
Per-Question QC Checklist0/6 complete

Common Mistakes Students Make on QC

These are the patterns that major ISEE prep resources — including Kaplan and Princeton Review — flag again and again. The good news is each one has a clean fix once you know it's coming. Naming these ISEE QC questions traps in advance is half the battle.

Misreading what is being compared

Misreading shows up in two main forms: students mix up which column is which, or they miss a constraint stated above the columns (like "x > 0" or "a is an integer"). The fix is to underline the constraint as soon as you see it, then write A and B labels on your scratch paper if the format ever feels confusing.

Plugging in only 1, 2, and 3

The single most common QC trap. If your test values share the same sign and similar size, the relationship between the columns rarely changes — but that does not mean the relationship is fixed. Always include -1, 0, and a fraction in your cycle, especially when squaring or multiplication is involved.

Choosing (D) just because the question is hard

Many students treat (D) as "I don't know," but on the ISEE it is a specific claim about the math. Use it only when test values prove the relationship is not fixed, or when you've shown the columns have multiple valid interpretations. If both columns are pure numbers, (D) is automatically wrong.

Remember: Slow your read, vary your test values, and don't pick (D) without checking the three rules from Strategy 3.

Practice Questions

Five practice quantitative comparison questions covering the four strategies above. Try each one before clicking through to the explanation.

Question 1 — Plug In Numbers
Given x is a real number, compare the two quantities. Column A: x squared. Column B: x.
Question 2 — Simplify First
Compare the two quantities. Column A: 47 + 88 + 19. Column B: 88 + 19 + 47.
Question 3 — Estimate to Compare
Compare the two quantities. Column A: 0.49 + 0.51 + 0.49. Column B: 1.6.
Question 4 — When (D) Cannot Be Right
Compare the two quantities. Column A: 17 percent of 200. Column B: 35.
Question 5 — Watch the Sign
Given y is a real number with y > 0, compare the two quantities. Column A: 2y. Column B: y + 5.

Tools to Practice With

Two helpers for the QC section: a pacing estimator that turns "57 seconds per question" into a real-time number for your study target, and a decoder that translates the relationship you've established into an answer choice.

🔢QC Time-Per-Question Estimator

Enter how many of the 37 Quantitative Reasoning questions you want to attempt and how many minutes you plan to keep in reserve, and we'll show your average pace.

🔄QC Answer Choice Decoder

Pick the relationship you've established between Column A and Column B. We'll tell you the corresponding answer choice and a one-line check.

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Frequently Asked Questions

No. Quantitative comparisons appear only on the Middle Level and Upper Level ISEE. The Lower Level Quantitative Reasoning section is made up entirely of word problems, so students taking the Lower Level test do not need to learn the Column A versus Column B format.

On the Middle and Upper Levels, the Quantitative Reasoning section has 37 questions in 35 minutes. Roughly 14 to 17 of those are quantitative comparison questions, with the remaining 18 to 21 being word problems. Five of the 37 questions are unscored experimental items that do not count toward your score.

Answer (D) means the relationship between Column A and Column B cannot be determined from the information given. It is correct only when more than one relationship is possible based on the constraints in the problem. (D) is never correct when both columns contain only fixed numbers, because fixed numbers always have a definite relationship.

No. Calculators are not permitted on any section of the ISEE, including Quantitative Reasoning. Students must rely on mental math, scratch work, and estimation. This is one reason the test rewards comparison strategies and order-of-magnitude thinking instead of exact calculation.

Start with -1, 0, and 1 to catch sign flips and squaring effects. Add a fraction between 0 and 1 to test how squaring or square roots reverse size. If small integers all give the same relationship, try a value larger than 5. If different test values give different answers, choose (D).

No. The ISEE has no guessing penalty, so every blank you leave is a missed scoring opportunity. On a quantitative comparison you cannot solve, eliminate any answer choices you can rule out and pick from what remains. Always fill in an answer for every question before time runs out.