I teach students to argue with evidence.

Mathematics at Yorktown High School. Algebra 1, Algebra 2 Intensified, and Data Science.

Show your reasoning.

Three courses,
one room

Five blocks a day. Each course keeps its own calendar, assignments and grades live in Canvas, and Data Science has a site of its own.

Data ScienceQuestion, collect, clean, draw, model, arguePeriod 1 · odd days
Algebra 2, IntensifiedFunction families, then probability and statisticsPeriods 3 and 7 · odd days
Algebra 1Equations, functions, quadratics, and data analysisPeriods 2 and 4 · even days

One year,
left to right

  • Quarter 1Aug 31 - Nov 2
  • Quarter 2Nov 4 - Jan 28
  • Quarter 3Feb 1 - Apr 16
  • Quarter 4Apr 20 - Jun 17
08AugustFirst day · Mon Aug 31
09SeptemberBack to School Night · Sept 30
10OctoberPSAT day · Oct 7
11NovemberQ1 ends Nov 2 · Thanksgiving
12DecemberWinter break from Dec 23
01JanuarySemester 1 ends · Jan 28
02FebruaryQ3 begins · Feb 1
03MarchSpring break · Mar 22-26
04AprilQ3 ends · Apr 16
05MayAP exams · May 3-14
06JuneFinal exams Jun 11-17 · Last day Jun 17
5blocksOne standardAn answer is finished when you can show how you got it. That is true in all five blocks.
678streetsEvery dataset has a sourceStudents work from published counts. The 678 street segments below were measured by VDOT, not by me.
0.975rThe line is fit, not drawnThe red line below is least squares through all 678 points. A number that says how well it fits comes with it.

Arlington traffic, 2015 against 2025

Traffic across these 678 street segments is down about four percent since 2015. The total hides what the streets did: 222 are busier, 340 are quieter, and 116 carry the same count in both years.

Average vehicles per day (2025)Average vehicles per day (2015)
  • Busier in 2025 222
  • Quieter in 2025 340
  • Counted the same 116
  • 2015 = 2025
  • Least-squares fit r = 0.975
Each dot is one Arlington street segment. Both axes are log-scaled, so every gridline is about three times the one below: that is what fits a 130-vehicle side street and a 92,000-vehicle interstate ramp in one frame. Hover or tap a dot for the street and its two counts. Counts from VDOT.

The work,
in five lines

  1. Lesson notesGuided notes built from Markdown lesson files. The builder refuses a page that overruns, and PDF and Word come from the same source.
  2. Which ChartStart with the job, not the picture: 41 chart types against the 13 things a chart can do, as Virginia publishes them, searchable.
  3. Calendars and pacingThree course calendars from one schedule model: odd and even days, closures, exam weeks, and a block-by-block fit of each course to its year.
  4. Arlington traffic, 2015 against 2025678 VDOT street segments, a least-squares fit with its r, and a loupe that names the street under the pointer.
  5. This siteNext.js over pages generated by a Python pipeline, one type system shared with every handout, deployed by the script that builds the notes.