Never Forget the 16 Essential Calculations
Stop memorizing. Start remembering. Proven mnemonic devices, visual triggers, and memory palace techniques to master every formula on test day.
Flashcards with formulas alone: Your brain treats them like random symbols
Rote repetition: You forget under pressure. Brain freeze on test day.
Generic "study tips": Nobody shows you WHAT to memorize or HOW
Similar formulas blur together: Current Yield vs Dividend Yield confusion
Specific mnemonics for ALL 16 formulas
Story-based anchors: Your brain LOVES stories
Visual triggers: What you picture, you remember
Anti-confusion strategies: Know what gets confused, prevent it
Recall formula under pressure: Memory palace technique
"I've watched hundreds of students fail the Series 65. Not because they didn't study. Because they tried to memorize formulas like vocabulary words. That doesn't work. This guide gives you exactly what those courses don't: specific memory devices that actually stick. You'll master these 16 formulas faster than you think."
Every formula in this guide uses this proven 4-part framework. Master the system, and every formula clicks.
Create or use an acronym or memorable phrase using first letters or words
Example:
Current Yield: 'Counting Your Annual Cash Money Prices' (CY = A/CMP)
Tell yourself a story connecting the formula to a real-world situation
Example:
At farmer's market, counting apples (interest) per dollar spent (price)
Create a mental image or scene. The weirder, the more memorable!
Example:
Literally COUNTING cash at market prices. Make it vivid.
Know what students get wrong and exactly how to avoid it
Example:
Use CURRENT price, not par value! This is where mistakes happen.
🧠 Neuroscience fact: Your brain remembers patterns, stories, and visuals MUCH better than raw numbers or abstract formulas.
⚡ Under pressure: When you're brain-tired on test day, a story or visual instantly unlocks the formula. Numbers alone? You blank.
🛡️ Confusion prevention: Knowing common mistakes BEFORE you see them stops you from making them under pressure.
📈 Retention: Multi-sensory learning (read mnemonic, hear story, visualize image) embeds formulas deeper and longer.
These appear on 50%+ of calculation questions. Get these locked in Week 1, and you're already ahead of 80% of test-takers.
Counting Your Annual Cash Money Prices
Acronym: CY = A / CMP
You're at a farmer's market (Current Market). A vendor hands you apples (Annual Interest). You're counting (CY) how many apples per dollar spent.
Picture yourself literally COUNTING (Current) cash at market prices
✕ Using par value instead of current price
✓ Current Yield uses CURRENT MARKET PRICE, not par value
✕ Confusing with Yield to Maturity
✓ Current Yield ignores capital gains/losses and time value
A bond pays $50 annual interest and trades at $1,000. What's the current yield?
Solution:
$50 ÷ $1,000 = 5%
Need A Value? Take Assets Less Liabilities, Split Over Shares
Acronym: NAV = (TA − L) / SO
A Navy ship (NAV) carrying Assets, throwing Liabilities overboard, then dividing treasure among Sailors (Shares Outstanding)
Picture a BALANCE SCALE: Assets on left, Liabilities being removed, then NET result divided into equal share bags
✕ Forgetting to subtract liabilities first
✓ SUBTRACT liabilities from assets BEFORE dividing by shares
✕ Using wrong denominator
✓ Always divide by SHARES OUTSTANDING, not number of investors
A mutual fund has $10M in assets, $500k in liabilities, and 500,000 shares. What's the NAV?
Solution:
($10,000,000 − $500,000) ÷ 500,000 = $19.00
Pay attention to Price per Earning
Acronym: P/E = Price / EPS
You're in PE class (Physical Education or P/E). The coach asks: How much did you PAY (Price) for each EXERCISE (Earning)?
Picture a price tag (P) divided by an earnings report (E)
✕ Thinking higher P/E = better investment
✓ Higher P/E = more expensive relative to earnings, NOT necessarily better value
✕ Confusing with EPS
✓ P/E is RATIO (valuation multiple), EPS is the earnings component alone
Stock trades at $50 with earnings per share of $2.50. What's the P/E ratio?
Solution:
$50 ÷ $2.50 = 20
Can Recent Assets Cover Liabilities?
Acronym: CR = CA / CL
You have CURRENT cash (Assets) to pay CURRENT bills (Liabilities). The ratio tells you if you're OK.
Picture two piles of money labeled 'NOW' (Current). One says ASSETS (green), one says LIABILITIES (red). Can green cover red?
✕ Not knowing what 'healthy' ratio is
✓ Ratio above 1.0 is generally healthy (can cover obligations). Below 1.0 is concerning.
✕ Confusing with Quick Ratio
✓ Current Ratio includes inventory. Quick Ratio excludes inventory (more conservative).
Company has $500k in current assets and $250k in current liabilities. Current ratio?
Solution:
$500,000 ÷ $250,000 = 2.0
4 bond formulas organized in "The Bond Market Building" - a 4-floor structure where each floor represents a formula
Floor 1 (Ground): Current Yield
Entrance level - counting cash at market prices
Floor 2 (Middle): Yield to Maturity
Where you settle - holding to maturity
Floor 3 (Call Button): Yield to Call
Red phone rings early - exit before peak
Floor 4 (Top): Accrued Interest
Daily accumulator - interest piling up each day
🧠 You Take Money: Add Interest + Gain Over Years, Average the Prices
You're climbing a mountain (Maturity). Each year you GAIN altitude (capital gain spread over years) PLUS collect interest payments at each campsite. The formula averages your position.
📍 Bond Market Building - Floor 2 (Middle, where you settle)
⚠️ Common Mistake
✕ Premium bonds: SUBTRACTING loss instead of adding gain
✓ If price > par (premium), subtract from interest. If price < par (discount), add to interest.
✕ Not averaging the prices
✓ Always use AVERAGE of par and current price as denominator
🧠 You're on Call Early: CALL price replaces PAR
Same mountain as YTM but there's a RED PHONE at the Call Price level. When it rings, you stop there instead of reaching the peak.
📍 Bond Market Building - Floor 3 (Call Button Floor - exits early)
⚠️ Common Mistake
✕ Using par instead of CALL PRICE
✓ YTC uses CALL PRICE and YEARS TO CALL, NOT maturity
✕ Forgetting YTC is lower when called early
✓ YTC often lower than YTM if bond called at premium
🧠 Annual Interest Daily: Divide 360, times Days
You're ACCUMULATING interest day by day. Think of a daily piggy bank filling up since the last interest payment.
📍 Bond Market Building - Floor 4 (Daily Accumulator Room)
⚠️ Common Mistake
✕ Using 365-day year instead of 360
✓ Bond math uses 360-day year (bond convention), NOT calendar year
✕ Forgetting seller receives accrued interest
✓ Buyer PAYS accrued interest to seller when purchasing between coupon dates
3 key stock metrics from "The Stock Exchange Floor"
Dividend Yield: Dollars You get per Price Paid
DIVE into a pool (Price). How deep is your YIELD (return)?
Picture dividend checks RAINING DOWN on a stock certificate priced at $X. How many checks per dollar?
⚠️ Common Mistake
✕ Using purchase price instead of current price
✓ Dividend Yield uses CURRENT price, not what you paid
✕ Confusing with Current Yield (bonds)
✓ Stocks pay DIVIDENDS (use Dividend Yield). Bonds pay INTEREST (use Current Yield).
Every Piece Shared: Net Income Split Out
A company earns NET income (after all expenses). It's like a pizza being cut into SHARES. Each slice is EPS.
PROFIT PIE being divided into equal SHARE slices
⚠️ Common Mistake
✕ Using revenue instead of net income
✓ EPS uses NET income (after all expenses and taxes), NOT revenue
✕ Confusing with P/E Ratio
✓ EPS is the EARNINGS component. P/E = Price ÷ EPS (the valuation multiple).
4 company health metrics from "The Company Health Clinic"
Quick Ratios Are Assets Ignoring Inventory
ACID TEST = emergency! You need QUICK cash. Inventory is too SLOW to convert, so subtract it.
⚠️ Common Mistake
✕ Forgetting to subtract inventory
✓ Quick Ratio subtracts inventory (illiquid). Current Ratio includes it.
✕ Not understanding it's more conservative
✓ Quick Ratio more conservative than Current Ratio (better for emergency assessment).
Debt Equity: Do Everyone Too much Debt?
You're measuring LEVERAGE. How much DEBT (borrowed money) vs EQUITY (owned money)?
⚠️ Common Mistake
✕ Thinking lower is always better
✓ Context matters. Some industries naturally have higher D/E (e.g., banks).
✕ Confusing higher ratio with stronger company
✓ Higher D/E = more leverage = more risky, NOT stronger
What's Currently Working: Assets minus Liabilities
Your WORKING capital is what you have to WORK with day-to-day. Assets you can use minus bills you owe.
⚠️ Common Mistake
✕ Thinking it's a ratio like current ratio
✓ Working Capital is a DOLLAR AMOUNT, not a ratio
✕ Confusing with Current Ratio
✓ Current Ratio = Assets ÷ Liabilities (ratio). Working Capital = Assets − Liabilities (dollar amount).
🎲 Master Rule: Calls = UP (add), Puts = DOWN (subtract)
This single rule separates correct from incorrect on options questions. Remember: Calls make money when stock goes UP. Puts make money when stock goes DOWN.
Call me UP: Strike + Premium
You CALL someone UP on the phone. Going UP means ADDING. Strike + Premium = Breakeven.
⚠️ Common Mistake
✕ Confusing buyer's and seller's breakeven
✓ Breakeven is SAME point, but buyer's profit is above, seller's is below it
✕ Subtracting premium instead of adding
✓ Calls use ADDITION (going UP). Puts use SUBTRACTION (going DOWN).
Puts go DOWN: Strike − Premium
You PUT something DOWN. Going DOWN means SUBTRACTING. Strike − Premium = Breakeven.
⚠️ Common Mistake
✕ Using addition instead of subtraction
✓ Puts use SUBTRACTION (opposite of calls)
✕ Forgetting puts profit when price goes DOWN
✓ Puts profit when stock price BELOW breakeven
Tax-Equivalent: Muni Divided by '1 minus Tax'
You want to compare MUNI (tax-free) to TAXABLE bonds. Divide muni by what you KEEP after taxes.
⚠️ Common Mistake
✕ Using percentage instead of decimal
✓ Convert tax rate to DECIMAL (32% = 0.32, not 32)
✕ Subtracting tax rate from yield directly
✓ Use formula (1 − Tax%), not just subtract
Real Return: Nominal Nets out Inflation
Your NOMINAL return is what you THINK you earned. REAL return is what your PURCHASING POWER actually gained after INFLATION.
⚠️ Common Mistake
✕ Ignoring inflation risk
✓ If inflation > return, real return is NEGATIVE (you lost purchasing power)
✕ Using wrong inflation rate
✓ Use actual inflation rate for the time period, not predicted
These formula pairs confuse students. Know them BEFORE test day.
🔄 Similarity
Both measure income return at current price
↔️ Key Difference
Current Yield = bonds (INTEREST). Dividend Yield = stocks (DIVIDENDS)
✓ Decision Tree
Is it a bond? → Current Yield. Is it a stock? → Dividend Yield.
🔄 Similarity
Both measure short-term liquidity
↔️ Key Difference
Quick Ratio excludes inventory (more conservative). Current Ratio includes it.
✓ Decision Tree
Need IMMEDIATE payment ability? → Quick Ratio. General liquidity check? → Current Ratio.
🔄 Similarity
Same formula structure
↔️ Key Difference
YTM = par value & maturity date. YTC = call price & call date (usually earlier)
✓ Decision Tree
Is bond callable? → YTC. Otherwise → YTM.
🔄 Similarity
Both relate to company earnings
↔️ Key Difference
P/E is valuation multiple (Price ÷ EPS). EPS is the profit component alone.
✓ Decision Tree
Valuation comparison? → P/E Ratio. Raw profitability? → EPS.
The memory palace (method of loci) is an ancient technique used by champions. Here's how to use it for Series 65 formulas.
A mental walkthrough of a familiar location (real or imaginary) where you place items you want to remember. Roman orators used this 2,000 years ago. It still works.
Your palace: "The Series 65 Formula Building" with 6 floors/areas, each containing rooms for specific formulas.
Priority Formulas
4 most commonly tested. Your entrance.
Bond Building
4 bond formulas. Current Yield to Accrued Interest.
3 Trading Desks
P/E, Dividend Yield, EPS.
4 Rooms
Current Ratio → Quick Ratio → D/E → Working Capital
2 Desks
Call goes UP. Put goes DOWN.
3 Departments
TEY, Real Return, NAV.
15 practice questions covering all 16 formulas. Each reinforces the mnemonic while building speed.
Options:
Correct Answer: 5%
CY = $60 ÷ $1,200 = 0.05 = 5%. Remember the mnemonic: Counting Your Annual Cash Money Prices. Use CURRENT price, not par.
Mnemonic Reminder:
Counting Your Annual Cash Money Prices
Options:
Correct Answer: 2.5x
$750k ÷ $300k = 2.5x. Ratio of 2.5 means $2.50 in assets for every $1 of liabilities. That's healthy (>1.0).
Mnemonic Reminder:
Can Recent Assets Cover Liabilities?
Options:
Correct Answer: 10x
$40 ÷ $4 = 10x. You're paying $10 for every $1 of earnings.
Mnemonic Reminder:
Pay attention to Price per Earning
Options:
Correct Answer: $25.00
NAV = ($50M − $5M) ÷ 2M = $45M ÷ 2M = $22.50. Subtract liabilities BEFORE dividing by shares.
Mnemonic Reminder:
Need A Value? Take Assets Less Liabilities, Split Over Shares
Options:
Correct Answer: 2.5%
$1.50 ÷ $60 = 0.025 = 2.5%. Uses CURRENT price, not purchase price.
Mnemonic Reminder:
Dollars You get per Price Paid
Options:
Correct Answer: 1.8x
($400k − $80k) ÷ $200k = $320k ÷ $200k = 1.6x. Quick ratio excludes inventory.
Mnemonic Reminder:
Quick Ratios Are Assets Ignoring Inventory
Options:
Correct Answer: $54
$50 + $4 = $54. Calls go UP, so you add. Stock must rise to $54 to break even.
Mnemonic Reminder:
Call me UP: Strike + Premium
Options:
Correct Answer: $46
$50 − $4 = $46. Puts go DOWN, so you subtract. Stock must fall to $46 to break even.
Mnemonic Reminder:
Puts go DOWN: Strike − Premium
Options:
Correct Answer: 6.2%
Top: $50 + ($100÷10) = $60. Bottom: ($1,900÷2) = $950. $60÷$950 = 6.3% ≈ 6.2%. Discount bond gives higher yield.
Mnemonic Reminder:
You Take Money: Interest + Gain Over Years, Average Prices
Options:
Correct Answer: 6.15%
4% ÷ (1 − 0.35) = 4% ÷ 0.65 = 6.15%. Tax-equivalent yield shows what taxable bond you'd need for same after-tax return.
Mnemonic Reminder:
Muni Divided by '1 minus Tax Rate'
Options:
Correct Answer: 33% higher
Old: $15M ÷ 6M = $2.50. New: $15M ÷ 5M = $3.00. That's 20% increase ($0.50÷$2.50 = 20%).
Mnemonic Reminder:
Every Piece Shared: Net Income Split Out
Options:
Correct Answer: 0.5x
New: Debt $3M ÷ ($7M + $2M) = $3M ÷ $9M = 0.33x ≈ 0.3x. Lower ratio means less leverage.
Mnemonic Reminder:
Debt to Equity: Measuring Leverage
Options:
Correct Answer: $27
($80 ÷ 360) × 120 = $0.222 × 120 = $26.67 ≈ $27. Bond math uses 360-day year.
Mnemonic Reminder:
Annual Interest Daily: Divide 360, times Days
Options:
Correct Answer: $200k
$600k − $400k = $200k. Working capital is a DOLLAR AMOUNT, not a ratio.
Mnemonic Reminder:
What's Currently Working: Assets minus Liabilities
Options:
Correct Answer: 8%
10% − 2% = 8%. Real return accounts for inflation eating into gains.
Mnemonic Reminder:
Real Return: Nominal minus Inflation
Master all 16 formulas with focused, progressive learning
Daily Goal
2 formulas per day, 30 minutes practice each
Milestone
Can recall all 4 mnemonics instantly without thinking
Activities
Daily Goal
Review Big 4 (10 min), master 1 new bond formula (30 min)
Milestone
Know YTM vs YTC difference. Can explain to someone else.
Activities
Daily Goal
Review previous 8 (15 min), master 1-2 new formulas (30 min)
Milestone
Can distinguish quick ratio from current ratio instantly
Activities
Daily Goal
Review all 16 (20 min), finish with 10 timed practice problems
Milestone
Score 80%+ on full 15-question practice test
Activities
All 16 formulas with mnemonics in one page. Print and study anywhere.
| Formula | Mnemonic Shortcut | Common Mistake |
|---|---|---|
| Current Yield | Counting Your Annual Cash Money Prices | Current Yield uses CURRENT MARKET PRICE, not par value |
| NAV (Net Asset Value) | Need A Value? Take Assets Less Liabilities, Split Over Shares | SUBTRACT liabilities from assets BEFORE dividing by shares |
| P/E Ratio | Pay attention to Price per Earning | Higher P/E = more expensive relative to earnings, NOT necessarily better value |
| Current Ratio | Can Recent Assets Cover Liabilities? | Ratio above 1.0 is generally healthy (can cover obligations). Below 1.0 is concerning. |
| Yield to Maturity (YTM) | You Take Money: Add Interest + Gain Over Years, Average the Prices | If price > par (premium), subtract from interest. If price < par (discount), add to interest. |
| Yield to Call (YTC) | You're on Call Early: CALL price replaces PAR | YTC uses CALL PRICE and YEARS TO CALL, NOT maturity |
| Accrued Interest | Annual Interest Daily: Divide 360, times Days | Bond math uses 360-day year (bond convention), NOT calendar year |
| Dividend Yield | Dividend Yield: Dollars You get per Price Paid | Dividend Yield uses CURRENT price, not what you paid |
| Earnings Per Share (EPS) | Every Piece Shared: Net Income Split Out | EPS uses NET income (after all expenses and taxes), NOT revenue |
| Quick Ratio (Acid Test) | Quick Ratios Are Assets Ignoring Inventory | Quick Ratio subtracts inventory (illiquid). Current Ratio includes it. |
| Debt-to-Equity Ratio | Debt Equity: Do Everyone Too much Debt? | Context matters. Some industries naturally have higher D/E (e.g., banks). |
| Working Capital | What's Currently Working: Assets minus Liabilities | Working Capital is a DOLLAR AMOUNT, not a ratio |
| Call Option Breakeven | Call me UP: Strike + Premium | Breakeven is SAME point, but buyer's profit is above, seller's is below it |
| Put Option Breakeven | Puts go DOWN: Strike − Premium | Puts use SUBTRACTION (opposite of calls) |
| Tax-Equivalent Yield | Tax-Equivalent: Muni Divided by '1 minus Tax' | Convert tax rate to DECIMAL (32% = 0.32, not 32) |
| Real Rate of Return | Real Return: Nominal Nets out Inflation | If inflation > return, real return is NEGATIVE (you lost purchasing power) |
💡 Print tip: Use landscape mode and 90% zoom for best fit
You now have the exact system used by top test-takers. Stop guessing. Start remembering.
By Mike Thompson | Updated February 2, 2026