mathinschool.com
numbers and algebraic expressions
logic, sets, intervals
absolute value
function and its properties
linear function
quadratic function
polynomials
rational function
exponential function
logarithm
number sequences
limits of sequences and functions
derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game

Examples: [2,5] - Closed interval. It contains numbers from 2 to 5. (2, 5) - Open interval. It contains numbers from 2 to 5 without 2 and 5. [2,5) - Interval closed on left and open on right. It contains numbers from 2 to 5 without 5. (2,5] - Interval open on left and closed on right. It contains numbers from 2 to 5 without 2. Brackets near infinity are always round. [2, ∞) - Interval closed on left and unbounded on right. It contains numbers greater than and equal to 2. (-∞, 5) - Interval unbounded on left and open on right. It contains numbers less than 5.