In algebra, letters are used to stand for values that can change (variables) or for values that aren’t known (unknowns). A term is a number or letter on its own, or numbers and letters ...

in the expression \(3(m + 7)\), multiply both \(m\) and 7 by 3, so: \(3(m + 7) = 3 \times m + 3 \times 7 = 3m + 21\). Expanding brackets involves using the skills of simplifying algebra.