Evaluate from inner-most outward

When you group terms in parentheses as in the previous slide, the operations inside the inner-most pair of parentheses will be fully evaluated before removing those parentheses and beginning the evaluation within of the next-outer pair of parentheses.

For example, the first form shown in the previous slide would add a to 3 and multiply the sum by 2.

The second form shown in the previous slide would multiply a by 2 and add the product to 3.