[size=150]Think of algebraic terms as areas of rectangles[br]For example [math]a\left(x+b\right)[/math] would be the area of a rectangle with length [math]x+b[/math] and breadth [math]a[/math].[br]When the rectangle is divided into two, along its length [math]x+b[/math], such that one has the length [math]x[/math] while the other has the length [math]b[/math] then there are two rectangles.[br]The areas of the rectangles [math]ax[/math] and [math]ab[/math] respectively. [br]Hence the original area [math]a\left(x+b\right)[/math] is equal to the sum of areas of the two rectangles [math]ax+ab[/math] .[br][br][br]The first example 3(5 + 2) shows two rectangles, one with length of 5 units and the other with length of 2 units, both having breadth of 3 units.[br]The areas of each rectangle is 3 x 5 = 15 square units and 3 x 2 = 6 square units. [br]Total area is 15+6 = 21 square units. [br]Now 3(5+2) is also 3 x 7 = 21 square units. [br]Hence using the area of rectangle as a model for multiplication of algebraic variables can provide a visual understanding of the expansion of algebraic expression in brackets.[/size]