When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Mental calculation - Wikipedia

    en.wikipedia.org/wiki/Mental_calculation

    The products of small numbers may be calculated by using the squares of integers; for example, to calculate 13 × 17, one can remark 15 is the mean of the two factors, and think of it as (15 − 2) × (15 + 2), i.e. 15 2 − 2 2. Knowing that 15 2 is 225 and 2 2 is 4, simple subtraction shows that 225 − 4 = 221, which is the desired product.

  3. Order of operations - Wikipedia

    en.wikipedia.org/wiki/Order_of_operations

    [2] [3] Thus, in the expression 1 + 2 × 3, the multiplication is performed before addition, and the expression has the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9. When exponents were introduced in the 16th and 17th centuries, they were given precedence over both addition and multiplication and placed as a superscript to the right of ...

  4. Trachtenberg system - Wikipedia

    en.wikipedia.org/wiki/Trachtenberg_system

    The Trachtenberg system is a system of rapid mental calculation.The system consists of a number of readily memorized operations that allow one to perform arithmetic computations very quickly.

  5. Equation solving - Wikipedia

    en.wikipedia.org/wiki/Equation_solving

    One particular solution is x = 0, y = 0, z = 0. Two other solutions are x = 3, y = 6, z = 1 , and x = 8, y = 9, z = 2 . There is a unique plane in three-dimensional space which passes through the three points with these coordinates , and this plane is the set of all points whose coordinates are solutions of the equation.

  6. Glossary of mathematical symbols - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_mathematical...

    3. Between two groups, may mean that the first one is a proper subgroup of the second one. > (greater-than sign) 1. Strict inequality between two numbers; means and is read as "greater than". 2. Commonly used for denoting any strict order. 3. Between two groups, may mean that the second one is a proper subgroup of the first one. ≤ 1.

  7. Algebraic operation - Wikipedia

    en.wikipedia.org/wiki/Algebraic_operation

    Plain text, programming languages, and calculators also use a single asterisk to represent the multiplication symbol, [6] and it must be explicitly used; for example, 3x is written as 3 * x. Rather than using the ambiguous division sign (÷), [ a ] division is usually represented with a vinculum , a horizontal line, as in ⁠ 3 / x + 1 ⁠ .

  8. Arithmetic - Wikipedia

    en.wikipedia.org/wiki/Arithmetic

    Decimal fractions like 0.3 and 25.12 are a special type of rational numbers since their denominator is a power of 10. For instance, 0.3 is equal to , and 25.12 is equal to . [20] Every rational number corresponds to a finite or a repeating decimal. [21] [c]

  9. Product (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Product_(mathematics)

    In mathematics, a product is the result of multiplication, or an expression that identifies objects (numbers or variables) to be multiplied, called factors. For example, 21 is the product of 3 and 7 (the result of multiplication), and x ⋅ ( 2 + x ) {\displaystyle x\cdot (2+x)} is the product of x {\displaystyle x} and ( 2 + x ) {\displaystyle ...