The math, science, computing, and habits every STEM career is built on.

STEM Foundations: The Universal Skill Stack

STEM work runs on **quantitative reasoning** — using numbers to describe and solve real problems. Three habits matter most:

- **Units.** A number without a unit is meaningless. "5" is nothing; "5 meters" is something. Always track units, and check that they match on both sides of an equation.
- **Estimation.** Before you calculate exactly, guess the rough size of the answer. If you expect "about 100" and your calculator says 0.01, you made a mistake somewhere.
- **Ratios and percentages.** Most real comparisons — speeds, prices, growth, doses — are ratios. Get comfortable moving between fractions, decimals, and percentages.

The goal isn't to memorize formulas. It's to take a messy real-world situation and turn it into numbers you can reason about.

Model a real problem with numbers, check units, and sanity-check answers.

Numbers, units, and estimation

Data is everywhere, and STEM careers live and die by reading it honestly.

- **Tables and charts** show patterns the raw numbers hide. Always read the axis labels and units first.
- **Averages** summarize, but they can mislead. One billionaire walking into a room changes the *average* income but not the *typical* income (the median).
- **Correlation is not causation.** Two things rising together doesn't mean one caused the other. Ice cream sales and drowning both rise in summer — because of heat, not because ice cream causes drowning.

When someone shows you a chart, ask: what's being measured, compared to what, and what's left out?

Make sense of tables and charts, and avoid the classic data traps.

Reading data: charts, averages, and cause vs. correlation

Numbers, units, estimation, and reading data without being fooled.