What’s new
We keep improving Maps for Math: fixing what readers and our own checks find, adding tools, and publishing new exhibits. Every change is listed here, newest first. Each exhibit also shows its own history at the bottom of its page.
76 exhibits published · 41 improvements · last updated November 8, 2026
November 2026
- ImprovedLoan payments: what a mortgage really costs · November 8, 2026New in the Use tab: compare loan lengths side by side, and a year-by-year amortization schedule. New worked case: a $750,000 loan at November 2026 average rates, 15 vs. 30 years and paying extra, with sources. New section on the most common mistakes, each with the wrong answer it gives.
October 2026
- ImprovedCrossing a river: where you aim vs. where you end up · October 7, 2026"Show the work" no longer shows floating-point dust (4×10⁻¹⁶ km/h) when aiming upstream exactly cancels the current; it now reads 0.
- ImprovedLoan payments: what a mortgage really costs · October 7, 2026Fix "Show the work": with an extra monthly payment, the total-interest step showed interest without the extra payment, which didn't match the result. Now shows both, plus interest saved.
- ImprovedSolar panel tilt: how much sunlight it catches · October 7, 2026"Show the work" no longer shows floating-point dust (e.g. 7.87×10⁻¹⁷ and 8.54×10⁻⁷°) where the value is exactly 0.
- ImprovedCrosswind landing: splitting the wind into two parts · October 2, 2026Limit input relabeled "max demonstrated crosswind (POH) or your personal limit"; 15 kt default kept.
- ImprovedE6B descent planning: when to start down · October 2, 2026Plan by descent rate (ft/min) as well as angle. Terrain and minimum-altitude note.
- ImprovedE6B time and fuel: will it make it with a reserve? · October 2, 2026Optional climb fuel from the POH climb table. 45-minute reserve relabeled "night VFR, or IFR after reaching the alternate", with a note that the alternate leg isn’t included.
- ImprovedE6B true airspeed: why you’re faster than the dial says · October 2, 2026Compressible true airspeed (Mach × speed of sound) with every step shown, up to 400 kt; the simple CAS/√σ is shown for comparison. CAS help text points to the POH calibration table.
- ImprovedE6B weight and balance: where the center of gravity lands · October 2, 2026Envelope corners from the POH chart replace the rectangle when entered. Landing check from fuel burned, and Jet A at 6.7 lb/gal. Opens blank on the exhibit page; examples load from "Try an example…".
- ImprovedE6B wind triangle: heading and groundspeed · October 2, 2026Wind direction can be entered true or magnetic. Optional compass deviation gives compass heading.
- ImprovedHow many amps does it draw? · October 2, 202680% wording names the NEC continuous-load rule; note when a load is over 80%. Resistive-only assumption stated, with the motor and compressor startup note.
- ImprovedSine waves: wall power and musical notes · October 2, 2026Optional second wave: a split-phase leg (with the voltage between legs) or a lagging current (with power factor). Mains peak-voltage safety note.
- ImprovedSizing a wire: load → current → voltage drop · October 2, 2026Wire resistance at 75 °C (drop now 5.25%), and a breaker step flagging 12.5 A over 80% of 15 A.
- ImprovedVoltage divider: two resistors make a new voltage · October 2, 2026Optional target voltage finds the nearest standard E12/E24 resistor pair. Battery-drain note when the divider draws 1 mA or more.
- ImprovedVoltage drop: what the wire takes before the load gets it · October 2, 2026Three-phase option, √3·I·R₁ line to line. Selectable drop target: 3% branch (default), 5% total, 2% stricter.
- ImprovedWire resistance: longer and thinner resist more · October 2, 2026Wire temperature choice, 75 °C by default to match NEC Ch. 9 Table 8. Metric sizes 1.5 to 25 mm² alongside AWG. Stranded-wire note in Use.
- ImprovedLoan payments: what a mortgage really costs · October 1, 2026Raise the loan amount slider maximum from $1,000,000 to $2,000,000.
September 2026
- New exhibitA 99% accurate test, and a positive is probably wrong · September 30, 2026
- New exhibitLottery odds: what is a ticket really worth? · September 30, 2026
- New exhibitMonty Hall: should you switch doors? · September 30, 2026
- New exhibitThe birthday problem: 23 people is a coin flip · September 30, 2026
- New exhibitCrossing a river: where you aim vs. where you end up · September 29, 2026
- New exhibitDistance from a speed graph: area under the curve · September 29, 2026
- New exhibitHanging a hammock: why the 30° rule works · September 29, 2026
- New exhibitHitting your macros: how much of three foods? · September 29, 2026
- New exhibitHow search ranks pages: links as votes (PageRank) · September 29, 2026
- New exhibitIs this investment worth it? The rate of return is a polynomial’s root · September 29, 2026
- New exhibitPhoto edits are matrices: rotate, flip, stretch, and slant · September 29, 2026
- New exhibitSolar panel tilt: how much sunlight it catches · September 29, 2026
- New exhibitSpeed from a position graph: the derivative · September 29, 2026
- New exhibitThe biggest box from a sheet of cardboard: optimization · September 29, 2026
- New exhibitWhy a distortion pedal changes the sound: polynomials make harmonics · September 29, 2026
- New exhibitA/B test: is version B really better, or just lucky? · September 28, 2026
- New exhibitMean vs. median: why one big paycheck skews the average · September 28, 2026
- New exhibitPoll margin of error: why about 1,000 people gives ±3% · September 28, 2026
- New exhibitThe bell curve: what percentile is that? · September 28, 2026
- New exhibitCrank and piston: turning rotation into back-and-forth · September 27, 2026
- New exhibitDC motor torque–speed curve: where it runs, peaks, and stalls · September 27, 2026
- New exhibitHooke’s law: how far does the car sag when you load it? · September 27, 2026
- New exhibitLead screw vs. ball screw: turning torque into a push · September 27, 2026
- New exhibitStress and strain: how much does a rod stretch under a load? · September 27, 2026
- New exhibitThe Bartz equation: how regenerative cooling keeps a rocket throat from melting · September 27, 2026
- New exhibitTorque: how hard to pull the wrench, and what an adapter changes · September 27, 2026
- ImprovedCompound interest: money that grows on itself · September 26, 2026Note that higher rates usually mean variable investment returns.
- ImprovedCrosswind landing: splitting the wind into two parts · September 26, 2026Join the E6B suite (badge, tool bar, flight-safety notice); link to VEC-0002.
- New exhibitDoor closer: slam, bounce, or glide · September 26, 2026
- ImprovedE6B density altitude, exact: standard atmosphere and humidity · September 26, 2026Becomes the exact tool: adds an optional dew point (humidity via virtual temperature). A blank dew point assumes 50% relative humidity, with a note. Links to the new rule-of-thumb tool LIN-0008, now the suite's main density altitude tool.
- New exhibitE6B density altitude, exact: standard atmosphere and humidity · September 26, 2026
- New exhibitE6B density altitude: the 120-feet-per-degree rule · September 26, 2026
- ImprovedE6B descent planning: when to start down · September 26, 2026Name the trainer preset "like a Cessna 172".
- New exhibitE6B descent planning: when to start down · September 26, 2026
- ImprovedE6B time and fuel: will it make it with a reserve? · September 26, 2026Name the cross-country preset "like a Cessna 172".
- New exhibitE6B time and fuel: will it make it with a reserve? · September 26, 2026
- ImprovedE6B true airspeed: why you’re faster than the dial says · September 26, 2026Name the trainer preset "like a Cessna 172".
- New exhibitE6B true airspeed: why you’re faster than the dial says · September 26, 2026
- ImprovedE6B weight and balance: where the center of gravity lands · September 26, 2026Describe the default airplane as about the size of a Cessna 172, with a clear note that the numbers are not its real ones.
- New exhibitE6B weight and balance: where the center of gravity lands · September 26, 2026
- New exhibitE6B wind triangle: heading and groundspeed · September 26, 2026
- New exhibitHome heat loss: where does the heat go? · September 26, 2026
- ImprovedHow many amps does it draw? · September 26, 2026Add a note on motor startup and running current.
- ImprovedHow much concrete for a slab? · September 26, 2026Note when the waste allowance is below the usual 5–10%.
- ImprovedHow much paint do I need for a room? · September 26, 2026Add a gentle coverage-variability note, shown only when the cans barely cover the job.
- New exhibitInsulation payback: how long until it pays for itself? · September 26, 2026
- ImprovedLoan payments: what a mortgage really costs · September 26, 2026Note that mortgage payments usually add tax and insurance.
- New exhibitPC cooling: passive, air, or water? · September 26, 2026
- New exhibitRapid cooling: 135 °F to 70 °F in two hours · September 26, 2026
- ImprovedRoad trip math: miles, liters, and dollars · September 26, 2026Add a gentle note on real-world fuel economy, shown on trips over 500 km.
- ImprovedRunning pace: from your 5K to a marathon time · September 26, 2026Note that long predictions from short races assume matching training.
- ImprovedThe rocket equation: why rockets are almost all fuel · September 26, 2026Note when Δv is too close to the orbit line to call.
- New exhibitWhen will my coffee wear off? · September 26, 2026
- New exhibitWhy the shower goes hot, then cold · September 26, 2026
- ImprovedWing lift: why twice the speed means four times the lift · September 26, 2026Add a note that stall speed is from a simplified wing model.
- ImprovedWire resistance: longer and thinner resist more · September 26, 2026Add a note on conductor temperature.
- New exhibitBrightness vs. distance: the inverse-square law · September 25, 2026
- ImprovedCompound interest: money that grows on itself · September 25, 2026Linked to the new exhibit “Loan payments: what a mortgage really costs.”
- New exhibitCooling coffee: when is it drinkable? · September 25, 2026
- New exhibitCredit card payoff: how many months until it’s gone? · September 25, 2026
- ImprovedCrosswind landing: splitting the wind into two parts · September 25, 2026Linked to the new exhibit “Wing lift: why twice the speed means four times the lift.”
- New exhibitCrosswind landing: splitting the wind into two parts · September 25, 2026
- ImprovedDecibels: why two speakers aren’t twice as loud · September 25, 2026Linked to the new exhibit “Credit card payoff: how many months until it’s gone?.”
- New exhibitDecibels: why two speakers aren’t twice as loud · September 25, 2026
- New exhibitHourly pay and overtime: time-and-a-half · September 25, 2026
- New exhibitHow many amps does it draw? · September 25, 2026
- ImprovedHow much concrete for a slab? · September 25, 2026Linked to the new exhibit “How much paint do I need for a room?.”
- New exhibitHow much concrete for a slab? · September 25, 2026
- New exhibitHow much paint do I need for a room? · September 25, 2026
- New exhibitJumping on the Moon: the same leap on other worlds · September 25, 2026
- New exhibitLoan payments: what a mortgage really costs · September 25, 2026
- New exhibitMixing solutions: how much of each? · September 25, 2026
- New formula familyOhm’s Law & Electrical Power · September 25, 2026
- New exhibitOrbits: how fast to go around and never come down · September 25, 2026
- New exhibitPercent change: up 50%, then down 50%, and you’ve lost money · September 25, 2026
- New exhibitRoad trip math: miles, liters, and dollars · September 25, 2026
- New exhibitRoof pitch and ramp slope: rise over run · September 25, 2026
- New exhibitRunning pace: from your 5K to a marathon time · September 25, 2026
- ImprovedSale price and tax: what you really pay · September 25, 2026Linked to the new exhibit “Percent change: up 50%, then down 50%, and you’ve lost money.”
- New exhibitSine waves: wall power and musical notes · September 25, 2026
- ImprovedSizing a wire: load → current → voltage drop · September 25, 2026Initial curated chain.
- New formula familySpeed, Distance & Time · September 25, 2026
- ImprovedSpeed, distance, time: how long is the drive? · September 25, 2026Linked to the new exhibit “Running pace: from your 5K to a marathon time.”
- New exhibitThe rocket equation: why rockets are almost all fuel · September 25, 2026
- ImprovedThrowing a ball: the quadratic arc · September 25, 2026Linked to the new exhibit “Jumping on the Moon: the same leap on other worlds.”
- New exhibitUnit price: is the big size really the better deal? · September 25, 2026
- New exhibitVoltage divider: two resistors make a new voltage · September 25, 2026
- New exhibitVoltage drop: what the wire takes before the load gets it · September 25, 2026
- New exhibitWing lift: why twice the speed means four times the lift · September 25, 2026
- New exhibitWire resistance: longer and thinner resist more · September 25, 2026
- New exhibitCompound interest: money that grows on itself · September 24, 2026
- New exhibitDice odds: what are my chances of rolling it? · September 24, 2026
- New exhibitHow tall is that tree? Measure its shadow · September 24, 2026
- New exhibitLadder against a wall: how high will it reach? · September 24, 2026
- New exhibitOhm’s law: how much current flows? · September 24, 2026
- New exhibitPhone plans: finding the break-even point · September 24, 2026
- New exhibitPizza value: one large or two mediums? · September 24, 2026
- New exhibitSale price and tax: what you really pay · September 24, 2026
- New exhibitScaling a recipe: more people, same taste · September 24, 2026
- New exhibitSpeed, distance, time: how long is the drive? · September 24, 2026
- New exhibitThe biggest garden from a fixed fence · September 24, 2026
- New exhibitThrowing a ball: the quadratic arc · September 24, 2026
Spotted a mistake, or want an exhibit we don’t have? Tell us.