Great! Let's go a little further. Until now, our calculations have relied on using just a single operator.
Operators have the same order of precedence you learned in school: multiplication and division have higher priority than addition and subtraction. Thus, if you type
1+2*3, R will return 7 and not 9.
When in doubt, you can always use parentheses to clarify the order in which operations should be performed. For example, the following two expressions:
(65 + 87) * 2.20
65 + 87 * 2.20
will give us entirely different results. This is because calculations within parentheses are evaluated before anything else, according to the standard order of operations.