In algebra, certain kinds of polynomials (expressions consisting of several or many terms) can be factorized using their common factors. Brackets are put into an expression, and the common factor is sought. For example, the factors of 2a2 + 6ab are 2a and a + 3b, since 2a2 + 6ab = 2a(a + 3b). This rearrangement is called factorization.
Green and red replaced blue and white as the national colours in 1910. The armillary sphere surrounds the shield of Portugal. Effective date: 30 June 1911.