Introduction
5. Basic arithmetic in one expression
Text values
Variables
Functions
Summary

## Instruction

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
and
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.

## Exercise

Tanya found another rule online for calculating ideal weight for females. This rule says to use the following formula:

45.5 + (0.9 * (height in cm - 152 ))

Calculate Tanya's ideal weight if you know that she is 172 cm tall. Don't forget to use parentheses where needed.