20×5

20×5 is a mathematical expression denoting the product of twenty and five. Evaluated in base ten, 20×5 equals 100, a basic result often used in elementary arithmetic to illustrate multiplication, scaling and repeated addition. The expression can be read as "twenty times five" and is symbolized using the multiplication sign (×); other notations include dot (20·5) or juxtaposition in algebraic contexts (20 5).

As an instance of multiplication, 20×5 exemplifies the commutative property (20×5 = 5×20) and can be interpreted as adding twenty to itself five times or five to itself twenty times. The prime factorization of the product is 2^2 × 5^2, since 20 = 2^2 × 5 and 5 is prime; this yields 100, which is also 10^2, a perfect square. In number theory, 100 is an even composite number with divisors 1, 2, 4, 5, 10, 20, 25, 50 and 100.

Beyond pure arithmetic, the notation 20×5 commonly appears in practical contexts to indicate dimensions, ratios or counts (for example, a 20×5 rectangle or a batch of 20 groups of 5). Representations of the value 100 include Roman numeral C, binary 1100100, and hexadecimal 64. The expression serves as a simple, frequently cited example when teaching basic multiplication concepts and properties.