- 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
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.
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?
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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?
- Divide 4.75 by 100 to obtain 0.0475.
- $360,000 x 0.0475 = $17,100.
- Five percent of $360,000 is $18,000, so a 4.75% result should be slightly lower.
- 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?
- Convert 0.5% to 0.005.
- $420,000 x 0.005 = $2,100.
- Using 0.5 would incorrectly calculate $210,000, or 50%.
- 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?
- 33 1/3% is exactly one-third.
- $450,000 / 3 = $150,000.
- Using 0.33 would produce only $148,500.
- 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?
- 1.375 points means 1.375% of loan amount.
- Convert to 0.01375.
- $320,000 x 0.01375 = $4,400.
- 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?
- Percentage-point increase is 6.5% - 6% = 0.5 percentage point.
- Relative increase is 0.5 / 6 = 0.0833333.
- Convert to approximately 8.33% relative increase.
- 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?
- Change is $460,000 - $400,000 = $60,000.
- Use original value as the base: $60,000 / $400,000 = 0.15.
- Convert 0.15 to 15%.
- 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?
- 0.00625
- 0.625
- 0.0625
- 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?
- 4.5%
- 45%
- 0.45%
- 450%
Show answer and explanation
Answer: 4.5%
Multiply 0.045 by 100 to obtain 4.5%.
3. What fraction equals 12.5%?
- 1 / 8
- 1 / 4
- 1 / 2
- 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?
- 0.75 percentage point
- 7.75 percentage points
- 10.71 percentage points
- 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?
- $2,250
- $225,000
- $4,000
- $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.
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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
- PSI Illinois Candidate Information Booklet dated June 24, 2026
- Illinois Department of Revenue, current assessment and equalized-assessed-value guidance
- Consumer Financial Protection Bureau, current points and lender-credits explanation
- Federal Reserve, official glossary definition of a basis point
- Consumer Financial Protection Bureau, current Regulation Z Loan Estimate requirements
- National Institute of Standards and Technology, percent as the number 0.01
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.