Short sets of exercises to build fluency. Every mistake has a name and is explained on the spot.

Inequalities

Secondary High school Algebra Equations

Isolating, multiplying and writing as intervals every kind of inequality, from the simplest to the rational ones.

Determinants

High school University Linear algebra Algebra

We start with 2×2 determinants and work through Sarrus and cofactors (minors) up to 4×4 matrices.

Ruffini's rule

Secondary High school Algebra Polynomials

Ordering and laying out the terms, running the algorithm and turning the result back into a polynomial.

Polynomial division

Secondary High school Algebra Polynomials

We work out how long division (with the box) works, and what the remainder means.

Derivatives: powers and roots

High school Calculus Derivatives

We start with the power rule, rewrite roots and fractions as powers, use the derivative for the tangent line, and end up differentiating (5 − 3x)⁷ with the chain rule.

Derivatives: elementary functions and the chain rule

High school Calculus Derivatives

We learn the table — sine, cosine, exponential, logarithm — and then differentiate functions nested inside others, up to two layers.

Limits: who wins

High school Calculus Limits

Limits in your head: polynomials at a point and at infinity, the three cases of rational functions, who grows faster among ln x, √x, x⁵ and eˣ, and the 0/0 and 1^∞ forms you can do once you know that near 0, sin x looks like x.

Powers

Secondary Algebra Powers

What a power is (negative exponents too: 5⁻² = 1/25), the rules for combining them, fractional exponents and roots, and how to simplify 36⁶/6¹¹ by changing the base. All with small numbers.

Logarithms

Secondary High school Algebra Logarithms

A logarithm is an exponent: work them out in your head (log₂(1/8) = −3 too), take the exponents of the base and the argument outside, combine log₃ 4.5 + log₃ 2 into a single logarithm, and solve equations like 3ˣ⁺¹ = 1/9.

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