Arithmetic

thumb|alt=The main arithmetic operator symbols; from left to right, top to bottom: addition sign +; minus sign −; multiplication sign ×; and division sign ÷.|The main arithmetic operations are addition, subtraction, multiplication, and division.|class=skin-invert-image

positive integer that has at least one positive divisor other than 1 or itself

thumb|right|The polynomial x2 + cx + d, where a + b = c and ab = d, can be factorized into (x + a)(x + b).

number that, when added to the original number, yields zero

product of any number and an integer

thumb|300px|link=https://upload.wikimedia.org/wikipedia/commons/8/8a/Comparison_rounding_graphs_SMIL.svg|Graph of a function|Graphs of the result, , of rounding using different methods. For clarity, the graphs are shown displaced from integer values. In the SVG file, hover over a method to highlight it and, in SMIL-enabled browsers, click to select or deselect it.

Dyscalculia is a learning disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, numeracy, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. It is sometimes colloquially referred to as "math dyslexia", though this analogy can be misleading as they are distinct syndromes.

any digit of a number within the measurement resolution of that number, as opposed to spurious digits

In mathematics, specifically in elementary arithmetic and elementary algebra, given an equation between two fractions or rational expressions, one can cross-multiply to simplify the equation or determine the value of a variable.

total non-primitive-recursive computable function

excess beyond the integer part of a number

method for bounding the errors of numerical computations

system of rapid mental calculation

presentation of numerical data in a manner that implies better precision than is justified

elementary operation on a natural number

in mathematics, named after Gabriel Sudan

class of mechanical calculator, usually specialized for bookkeeping calculations

Prosthaphaeresis (from the Greek προσθαφαίρεσις) was an algorithm used in the late 16th century and early 17th century for approximate multiplication and division using formulas from trigonometry. For the 25 years preceding the invention of the logarithm in 1614, it was the only known generally applicable way of approximating products quickly. Its name comes from the Greek prosthen (πρόσθεν) meaning before and aphaeresis (ἀφαίρεσις), meaning taking away or subtraction.

an arithmetic error

model of (first-order) Peano arithmetic that contains non-standard numbers