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The short version A Venn diagram uses overlapping circles to sort things into groups. The overlap holds items that belong to both groups, and the space outside every circle holds items that belong to none. For two groups, the total in at least one circle is A + B – both. You subtract the overlap…
The short version A parallelogram is a four sided shape where both pairs of opposite sides are parallel. Opposite sides are also equal in length. Opposite angles are equal, and any two angles next to each other add up to 180°. Area = base × height, where the height is the straight up and down…
The short version A variable in math is a letter or symbol that stands for a number you don’t know yet, or a number that can change. In 3x + 5, x is the variable, 3 is the coefficient (the number multiplying it), and 5 is the constant (a number that never changes). A number…
The short version Proportional means two quantities always change by the same factor: double one and the other doubles, cut one in half and the other halves. In a table, a relationship is proportional when y ÷ x gives the same number in every row. That number is the constant of proportionality, k. Every proportional…
The short version The independent variable is the input: the thing you choose, change, or control. The dependent variable is the output that changes because of it. Test it with a sentence: “[dependent] depends on [independent].” Test score depends on hours studied, so hours studied is the independent variable. On a graph, the independent variable…
The short version A square unit is a square that measures 1 unit on every side. Area is the number of those squares it takes to cover a flat shape with no gaps or overlaps. Square units are written with a small 2: cm², m², in², ft². You’ll also see “sq ft” or “square inches.”…
The short version Cubed means a number multiplied by itself three times. 4 cubed is written 4³ and equals 4 × 4 × 4 = 64. The little raised 3 is an exponent. It tells you how many copies of the number to multiply, so 4³ is never 4 × 3. The first twelve cube…
The short version An inequality is a math sentence that says two values aren’t equal, using a symbol like <, >, ≤, ≥ or ≠. x > 5 means “x is greater than 5.” It has endless answers (6, 7.5, 100 and so on), which is why we graph it on a number line. You…
The short version The order of operations is the agreed rule for which part of a math problem to do first: parentheses, then exponents, then multiplication and division, then addition and subtraction. PEMDAS and BEDMAS are two acronyms for the same order. B for brackets means the same thing as P for parentheses. Multiplication and…
The short version Ordinal numbers tell position or rank: first, second, third, 4th, 10th, 21st. They answer “which one?” or “what place?” Cardinal numbers tell how many (one, two, three). Nominal numbers are labels, like a jersey number or ZIP code. Most ordinals end in th. The exceptions end in st, nd or rd (1st,…