MeridianSAT prep

Desmos academy

The Digital SAT puts a graphing calculator on every math question. These ten lessons follow the same techniques as LearnSATMath’s Desmos guide — regressions, intersections, overlays — with original problems you can try immediately. Practice items are the ugly SAT-style ones that take minutes on paper and about 20 seconds in Desmos. Master a lesson by hitting two of the three practice questions.

Before the lessons

Memorize this

Vertex form, what a does to a parabola, the circle equation, typing ≤ as <=, x1/y1 vs x/y, tilde regression (including quadratic and cubic), and cbrt / sqrt / nthroot / mean. Plus the radians trap.

Open the notebook

Lesson 01 is free. The rest are on the Season Pass.

  1. 01Functions & regressions

    Up next

    Two points do not mean ‘write point-slope.’ Type table, then Add regression — or a custom tilde like y₁ ~ a/(x₁ − b). Ugly coefficients fall out in one click.

  2. 02Systems of equations

    6 min

    Two equations, two graphs. Click the intersection. When a letter is unknown (exactly one solution), add a slider and drag until the curves kiss.

  3. 03Single-variable equations

    6 min

    Turn one ugly equation into a system: y = left side, y = right side. Intersections are solutions. This is more precise than typing the equation as a vertical line.

  4. 04Inequalities

    5 min

    Type the inequality; Desmos shades the solution. For a system, the answer lives in the overlap. Max and min are on the border — not always at a ‘pretty’ intersection.

  5. 05Equivalent expressions

    7 min

    If two expressions are equivalent, their graphs are the same curve. Graph the given, graph each choice, keep the match. For ‘find a, b, c,’ use expression ~ ax²+bx+c with x₁ = [1,2,3,4,5].

  6. 06In terms of

    6 min

    When the answer is an expression in k (or a, b, p…), pick a number for the extra letter and see which choice matches. Regression with ~ works only if there is one solution.

  7. 07Element lists

    6 min

    Pack several conditions into one line: [left1, left2] ~ [right1, right2]. Perfect for ‘a+b and ab’ or a quadratic pinned by two points and a vertex.

  8. 08Mean & median

    4 min

    mean(list), median(list), max(list)−min(list) for range. A missing value that makes the mean 80 is a one-line regression: mean([…, n]) ~ 80. Don’t use x — that’s the graph axis, and Desmos will throw a warning.

  9. 09Geometry & trig in Desmos

    5 min

    First move on any SAT trig item: wrench → degrees. Desmos starts in radians. sin(30) in radians is not ½. Circles: paste the equation and click the gray center and an endpoint.

  10. 10When not to use Desmos

    4 min

    About a quarter of SAT Math will not yield to the calculator. Word-problem translation, most geometry, conceptual statistics, and ‘same line / no solution’ as a concept still need your brain. Opening Desmos here is a time tax.

Techniques adapted from publicly taught Desmos SAT methods (including LearnSATMath). Problems in Meridian are original.