4x7

4x7 denotes the product of 4 and 7 in arithmetic, equal to 28. In mathematics, the expression is read as four by seven or four times seven; due to the commutative property, 4×7 = 7×4. The result, 28, is a perfect number because the sum of its proper divisors (1, 2, 4, 7, 14) equals 28. It is also a triangular number, being the seventh triangular number, calculated as 7×8/2 = 28.

The phrase 4x7 is also used to describe dimensions: a rectangle that is 4 units wide by 7 units tall (or long). The units may be inches, centimeters, or other measures, and the phrase appears in contexts such as photo prints, tiles, textiles, and display layouts.

In practical applications, 4x7 can describe grid sizes, such as a 4-by-7 matrix (4 rows and 7 columns) or a 4×7 dot-matrix LED display, common in electronics projects. A 4x7 grid contains 28 cells, which can be used for combinatorial counting or puzzle design.

The term appears in both mathematical discussions and everyday description of size and layout, with the emphasis on the integer factors and the resulting product.