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Real estate math guide

Percent means divide by one hundred

Real estate formulas rarely fail because multiplication stopped working. They fail because 0.5% became 0.5, 1.25 points became 1.25, or one-third became 0.33 too early. Convert the rate on its own line, estimate whether the result should be tiny or substantial, and only then apply it to the correct base. The habit feels slow for the first few drills. By exam day, it is faster than repairing a calculator entry that is off by a factor of 100.

Last updated: August 1, 2026

What calculation do you need to make?

Short answer: Percent to decimal: divide by 100. Decimal to percent: multiply by 100. Fraction to decimal: divide numerator by denominator. Fraction to percent: divide, then multiply by 100. Percent to fraction: place the percent over 100, clear any decimal, and simplify. Use decimal form for multiplication, percentage form for a requested rate, and exact fraction form when it prevents repeating-decimal rounding. One mortgage point is 1% of the loan amount, so 1.375 points becomes 0.01375. An increase from 6% to 6.5% is 0.5 percentage point, not a 0.5% relative increase. One basis point is one-hundredth of a percentage point. Always state the base because the same rate produces different dollar amounts when applied to sale price, loan amount, value, taxable EAV, or another total. Preserve the printed precision during working steps, then round only as directed. A calculator display without a label is unfinished work: 0.08 may mean a decimal rate, while 8% is the same value in the form the question may request. Make conversion visible. Write 4.5% = 0.045, label the base, and estimate 5% of that base. If the answer is supposed to be a rate, divide part by base first and convert the quotient back to percent only at the end. For a repeating fraction, retain the fraction or several guard digits rather than replacing one-third with 0.33. When two rates appear, ask whether they share a base. A 60% brokerage share followed by a 70% licensee share produces 42% of the original amount because the second percentage applies to the brokerage share. This routine catches decimal shifts, wrong denominators, premature rounding, and rates applied to the wrong subtotal before they reach the answer choices.

Official section
National XI: Real Estate Math
Broker weight
A foundation skill supporting all named calculation families
Expected scored items
The current PSI broker outline assigns about 7 of 100 scored national items to Real Estate Math

This page teaches numeric representation, not which real-world rate or base applies. Current tax, lending, compensation, valuation, and settlement facts come from official records, agreements, disclosures, and applicable rules. Illinois assessment examples require attention to county and property type; mortgage points use loan amount; actual lender pricing varies. The Department of Revenue says most Illinois property is assessed at 33 1/3% of fair market value, while Cook County classifications, farmland, and preferential assessments can differ. That makes one-third useful exam math, not a universal parcel assumption. The federal forms can use percentages, dollar amounts, or both, but a study conversion does not replace the disclosed term. Sources were checked through August 1, 2026.

How do you convert and use real estate percentages?

  1. Circle the printed form and the form required for the next operation or final answer. Write both labels so a bare calculator number cannot drift into the wrong form.
  2. Convert percent to decimal by dividing by 100, decimal to percent by multiplying by 100, or fraction to decimal by division. Show the direction before moving the point.
  3. Preserve exact fractions for one-third and other repeating values until the final step when practical. If decimal entry is necessary, carry enough digits to protect the final answer.
  4. Name the base in words, such as loan amount for points or original value for percentage change. Do not let the largest number in the stem become the base automatically.
  5. Use part = base x decimal rate, reversing with division when base or rate is unknown. Label the quotient before deciding whether to display it as decimal or percent.
  6. For sequential percentages, write a new base before each rate is applied. A brokerage split, property-tax sequence, or successive value change may use a different base at every line.
  7. Carry quoted precision and round only the final result according to the question. Keep an exact fraction available as a parallel check for repeating values.
  8. Convert back, estimate magnitude, and check for a 100-times decimal-placement error. Also substitute the answer into the original relationship to see whether it recreates the given amount.
Fraction
1 / 2
Decimal
0.5
Percent
50%
Fraction
1 / 3
Decimal
0.333333 repeating
Percent
33 1/3%
Fraction
2 / 3
Decimal
0.666667 approximately
Percent
66 2/3%
Fraction
1 / 4
Decimal
0.25
Percent
25%
Fraction
3 / 4
Decimal
0.75
Percent
75%
Fraction
1 / 5
Decimal
0.2
Percent
20%
Fraction
1 / 8
Decimal
0.125
Percent
12.5%
Fraction
3 / 8
Decimal
0.375
Percent
37.5%
Fraction
5 / 8
Decimal
0.625
Percent
62.5%
Fraction
7 / 8
Decimal
0.875
Percent
87.5%

Can you follow the calculation from facts to answer?

Convert a fractional commission rate

Scenario: A brokerage fee is 4.75% of a $360,000 stated base. What decimal is used and what fee results?

  1. Divide 4.75 by 100 to obtain 0.0475.
  2. $360,000 x 0.0475 = $17,100.
  3. Five percent of $360,000 is $18,000, so a 4.75% result should be slightly lower.
  4. The calculated $17,100 fits that estimate and keeps sale price as the stated base.

Answer: Use 0.0475; the fee is $17,100.

Handle a rate below one percent

Scenario: A stated fee is 0.5% of a $420,000 base. What is the fee?

  1. Convert 0.5% to 0.005.
  2. $420,000 x 0.005 = $2,100.
  3. Using 0.5 would incorrectly calculate $210,000, or 50%.
  4. One percent is $4,200, so one-half of 1% must be $2,100.

Answer: The fee is $2,100.

Use exact one-third assessment math

Scenario: A simplified question states an assessment level of exactly 33 1/3% on a $450,000 market value. What is assessed value?

  1. 33 1/3% is exactly one-third.
  2. $450,000 / 3 = $150,000.
  3. Using 0.33 would produce only $148,500.
  4. The $1,500 gap shows why early rounding matters on a large base.

Answer: The assessed value is $150,000.

Convert fractional mortgage points

Scenario: A borrower pays 1.375 points on a $320,000 loan. What decimal and charge apply?

  1. 1.375 points means 1.375% of loan amount.
  2. Convert to 0.01375.
  3. $320,000 x 0.01375 = $4,400.
  4. One point is $3,200, and 0.375 point is $1,200, which confirms the total.

Answer: Use 0.01375; the point charge is $4,400.

Separate percentage points from relative change

Scenario: A rate rises from 6% to 6.5%. What are the percentage-point increase and relative percent increase?

  1. Percentage-point increase is 6.5% - 6% = 0.5 percentage point.
  2. Relative increase is 0.5 / 6 = 0.0833333.
  3. Convert to approximately 8.33% relative increase.
  4. State which measure you are reporting because both figures answer different questions.

Answer: The rise is 0.5 percentage point, or about 8.33% relative to the original rate.

Calculate percentage appreciation

Scenario: A property rises from $400,000 to $460,000. What is the percentage increase?

  1. Change is $460,000 - $400,000 = $60,000.
  2. Use original value as the base: $60,000 / $400,000 = 0.15.
  3. Convert 0.15 to 15%.
  4. Reverse-check: $400,000 x 1.15 = $460,000.

Answer: The property appreciated 15%.

Which math errors cost the most points?

Trap
Multiply by the printed percent without converting.
Correction
Divide the percent by 100 before using it as a multiplier.
Trap
Convert 0.5% to 0.5.
Correction
0.5% equals 0.005; 0.5 equals 50%.
Trap
Convert 1.25 to 1.25%.
Correction
The decimal 1.25 equals 125%.
Trap
Drop leading zeros from a small decimal rate.
Correction
Write 0.0075 for 0.75% so the place value remains clear.
Trap
Round one-third to 0.33 before multiplying.
Correction
Use 1 / 3 or sufficient repeating-decimal precision.
Trap
Treat 1.375 mortgage points as a multiplier of 1.375.
Correction
Convert 1.375% to 0.01375 and use loan amount as base.
Trap
Call a 0.5 percentage-point rise a 0.5% relative increase.
Correction
Divide the rate difference by the original rate for relative percent change.
Trap
Treat one basis point as 1 percentage point.
Correction
One basis point is 0.01 percentage point.
Trap
Use ending value as the percentage-change base.
Correction
Use original value unless the question defines another comparison.
Trap
Use purchase price as the base for mortgage points.
Correction
Points are percentages of loan amount.
Trap
Apply successive rates to the original base automatically.
Correction
Relabel the base at each step from the facts.
Trap
Give a decimal when the answer asks for percent.
Correction
Convert the quotient by multiplying by 100 and include the percent sign.

Can you solve these original problems?

These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.

1. What is 0.625% as a decimal?

  1. 0.00625
  2. 0.625
  3. 0.0625
  4. 6.25
Show answer and explanation

Answer: 0.00625

Divide 0.625 by 100 to obtain 0.00625.

2. What is 0.045 as a percent?

  1. 4.5%
  2. 45%
  3. 0.45%
  4. 450%
Show answer and explanation

Answer: 4.5%

Multiply 0.045 by 100 to obtain 4.5%.

3. What fraction equals 12.5%?

  1. 1 / 8
  2. 1 / 4
  3. 1 / 2
  4. 3 / 4
Show answer and explanation

Answer: 1 / 8

12.5% = 0.125 = 125 / 1000 = 1 / 8.

4. A rate rises from 7% to 7.75%. What is the change in percentage points?

  1. 0.75 percentage point
  2. 7.75 percentage points
  3. 10.71 percentage points
  4. 75 percentage points
Show answer and explanation

Answer: 0.75 percentage point

7.75% - 7% = 0.75 percentage point.

5. A $300,000 loan is charged 0.75 points. What is the point cost?

  1. $2,250
  2. $225,000
  3. $4,000
  4. $22,500
Show answer and explanation

Answer: $2,250

0.75 points = 0.75% = 0.0075; $300,000 x 0.0075 = $2,250.

Which numbers and formulas are easy to confuse?

Terms
Percent vs. decimal
Difference
Percent states a rate per hundred. Decimal expresses the same ratio in calculator-ready place value.
Question cue
6% label versus 0.06 multiplier.
Terms
Decimal vs. fraction
Difference
A decimal uses place value. A fraction expresses a numerator relative to a denominator and can preserve exact repeating values.
Question cue
0.25 versus 1 / 4.
Terms
Percent vs. percentage point
Difference
Percent can describe relative change. A percentage point is the arithmetic difference between two percentage rates.
Question cue
Relative movement versus rate spread.
Terms
Percentage point vs. basis point
Difference
One percentage point equals 100 basis points. One basis point equals 0.01 percentage point.
Question cue
Whole rate point versus one-hundredth of it.
Terms
Rate vs. percentage amount
Difference
Rate is the proportional relationship. Percentage amount is the dollar or quantity part produced from the base.
Question cue
4% versus $16,000.
Terms
Base vs. part
Difference
Base is the whole to which the rate applies. Part is the amount representing that rate of the base.
Question cue
Loan amount versus point cost.
Terms
One-third vs. 0.33
Difference
One-third equals 0.333333 repeating. The decimal 0.33 equals exactly 33 / 100 and is smaller.
Question cue
Exact repeating ratio versus rounded approximation.
Terms
Point quote vs. interest-rate change
Difference
A mortgage point quote is a percentage of loan amount. The amount of interest-rate reduction per point is not universally fixed.
Question cue
Dollar-cost rate versus loan-pricing result.
Terms
Percent of original vs. percent of new amount
Difference
Percentage change ordinarily uses the original amount. Reversing the denominator answers a different question.
Question cue
Starting base versus ending base.
Terms
Successive change vs. net added rates
Difference
Successive percentages can use different bases. Adding the printed rates ignores compounding or base changes.
Question cue
Recalculated base versus shortcut sum.

What does the outline expect you to calculate?

Topic
Meaning of percent
What to know
Per hundred, ratio, rate, part, whole, base, percent sign, 100, proportion, and comparison
Best exam move
Read x percent as x divided by 100 before calculating a dollar amount.
Topic
Percent to decimal
What to know
Divide by 100, move decimal left, leading zero, percentage rate, multiplier, 6 percent, 0.06, and calculator entry
Best exam move
Write the decimal conversion beside the printed percent before multiplication.
Topic
Decimal to percent
What to know
Multiply by 100, move decimal right, percent sign, answer rate, 0.08, 8 percent, ratio, and reporting
Best exam move
Convert a divided rate back to percentage form when the question asks for percent.
Topic
Fraction to decimal
What to know
Numerator, denominator, division, terminating decimal, repeating decimal, exact fraction, one-half, one-third, one-eighth, and precision
Best exam move
Divide numerator by denominator but preserve exact fractional meaning when possible.
Topic
Fraction to percent
What to know
Decimal, multiply by 100, percent sign, quarter, half, three-fourths, one-fifth, one-eighth, and share
Best exam move
Convert through decimal or scale the fraction to a denominator of 100.
Topic
Percent to fraction
What to know
Over 100, simplify, greatest common factor, decimal percent, clear decimal, 25 percent, 12.5 percent, and exact ratio
Best exam move
Place the number over 100, clear decimal places, and reduce fully.
Topic
Rates below one percent
What to know
0.5 percent, 0.25 percent, 0.125 percent, leading zeros, transfer rate, fee, point fraction, decimal shift, and magnitude
Best exam move
Expect at least two zeros after the decimal before the first nonzero digit for many sub-one-percent rates.
Topic
Rates above 100 percent
What to know
125 percent, 150 percent, decimal above one, increase, multiplier, comparison, assessment factor, growth, and reasonableness
Best exam move
Recognize that a rate above 100% becomes a decimal greater than one.
Topic
Mixed-number percent
What to know
33 1/3 percent, 6 1/4 percent, whole number, fractional part, exact fraction, repeating decimal, and assessment level
Best exam move
Combine the mixed percent accurately before dividing by 100 or use its exact fractional equivalent.
Topic
Fractional mortgage points
What to know
One point, one percent, loan amount, 1.375 points, 0.01375, point cost, closing, and rate pricing
Best exam move
Treat the points quote as a percent of loan amount and divide by 100.
Topic
Percentage points
What to know
Rate difference, 6 percent, 6.5 percent, subtraction, 0.5 percentage point, relative change, and clear communication
Best exam move
Subtract two rates for percentage-point change; divide that difference by the original rate for relative percent change.
Topic
Basis points
What to know
One basis point, 0.01 percentage point, 0.0001 decimal, 100 basis points, rate spread, financing, and precision
Best exam move
Convert basis points to percentage points before turning the rate into a decimal multiplier.
Topic
Percentage part
What to know
Base, decimal rate, multiplication, commission, down payment, point cost, tax, assessed value, depreciation amount, and share
Best exam move
Multiply the correct base by the decimal rate.
Topic
Recover the base
What to know
Known part, known rate, division, sale price, loan amount, market value, total fee, original value, and reverse relationship
Best exam move
Divide the part by the decimal rate, not by the printed whole-number percent.
Topic
Recover the rate
What to know
Known part, known base, division, decimal quotient, percent conversion, LTV, cap rate, commission rate, and assessment level
Best exam move
Divide part by base and multiply by 100 for a percentage answer.
Topic
Percentage change
What to know
Original amount, new amount, change amount, increase, decrease, difference, original base, appreciation, depreciation, and rate
Best exam move
Divide change by original amount, not by the new amount.
Topic
Sequential percentages
What to know
Commission split, assessment then tax, appreciation then depreciation, successive change, new base, subtotal, multiplication, and nonadditive rates
Best exam move
Apply each percentage to its stated base and relabel the result before the next step.
Topic
Reasonableness check
What to know
Magnitude, less than one, greater than one, 100-times error, part versus base, inverse conversion, estimate, and unit
Best exam move
Convert back to the original form and ask whether the part's size fits the rate.

How should you drill this calculation?

Session
Session 1
Focus
Convert percent and decimal
Proof you are ready
Complete 50 two-way conversions, including rates below 1% and above 100%, with no place-value error.
Session
Session 2
Focus
Convert common fractions
Proof you are ready
Write decimal and percentage equivalents for halves, thirds, quarters, fifths, eighths, and mixed examples.
Session
Session 3
Focus
Use rates in formulas
Proof you are ready
Solve 30 part, base, and rate questions while labeling the correct real estate base.
Session
Session 4
Focus
Handle fractional points and assessment levels
Proof you are ready
Complete 20 mortgage-points and 20 exact-fraction assessment calculations without early rounding.
Session
Session 5
Focus
Separate rate-change language
Proof you are ready
Distinguish percentage points, relative percent change, and basis points in 30 prompts.
Session
Session 6
Focus
Complete a mixed conversion set
Proof you are ready
Score at least 90% and justify every representation, base, multiplier, denominator, rounding choice, final unit, and reasonableness estimate. Redo each miss from a blank page the next day so the corrected method, rather than the remembered option, drives the answer.

Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.

Build speed without skipping the setup

From concept to decision

Drill this topic, then review the explanation

Pass Illinois gives you original national and Illinois questions, topic-by-topic study, clear explanations, timed practice, flashcards, progress tracking, and Math Coach. Start free, find the weak distinction, and focus the next session there.

Questions students ask about Percent, Decimal, and Fraction Conversions: Illinois Exam Guide

How do you convert a percent to a decimal?

Divide by 100 or move the decimal point two places left. Thus 6% becomes 0.06, 4.5% becomes 0.045, and 0.75% becomes 0.0075. Keep the leading zeros because they show the rate's true size.

How do you convert a decimal to a percent?

Multiply by 100 or move the decimal point two places right, then add the percent sign. Thus 0.08 becomes 8%, 0.125 becomes 12.5%, and 1.2 becomes 120%.

How do you convert a fraction to a decimal and percent?

Divide numerator by denominator to obtain the decimal, then multiply by 100 for percent. Three-fourths equals 3 / 4 = 0.75 = 75%. Preserve an exact fraction when a repeating decimal would otherwise create early rounding.

How do you convert a percent to a fraction?

Write the percent over 100 and simplify. For 25%, write 25 / 100 and reduce to 1 / 4. For 12.5%, write 12.5 / 100, clear the decimal to obtain 125 / 1000, and reduce to 1 / 8.

What is 33 1/3% as a decimal?

It is one-third, or 0.333333 repeating. When a problem uses exactly 33 1/3%, multiply by 1 / 3 or divide by 3 when possible. Entering 0.33 substitutes 33% and can materially understate the result.

What is 0.5% as a decimal?

It is 0.005. The leading zero matters. Multiplying by 0.5 would calculate 50%, which is 100 times the intended rate.

How do fractional mortgage points convert to a decimal?

Points are percentages of the loan amount. A quote of 1.375 points means 1.375%, or 0.01375 as a multiplier. It does not mean 137.5% and does not use purchase price as its ordinary base.

What is the difference between percent and percentage points?

A rate rising from 6% to 6.5% rises by 0.5 percentage point. Relative to the original 6%, the increase is 0.5 / 6, or approximately 8.33%. The two statements answer different questions.

What is one basis point?

One basis point is 0.01 percentage point, which is 0.0001 as a decimal. One hundred basis points equal 1 percentage point. Use basis-point language only when the question supplies it.

Are these official Illinois broker exam questions?

No. They are original conversion drills aligned to the PSI Illinois broker outline effective June 24, 2026. The current PSI outline and primary sources for the underlying real estate examples were checked through August 1, 2026.

Primary sources

The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.

Editorial status

Checked against primary sources

The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.

Read our editorial and corrections process

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