# 6  R as a calculator

Before we start

You must

• have installed both R and RStudio on your computer (Section 2.2).
• configured RStudio (Section 2.4)
• know how to install and activate a package (Chapter 5)

## 6.1 Basic operations in R

### 6.1.1 Arithmetic operations

Performing arithmetic operations is no big deal in R. Simply write any operation using the usual arithmetic operators `+`, `-`, `*` and `/` and run your code. No need to type `=`.

``5 + 3``
``[1] 8``
``9 * 2``
``[1] 18``
``14 / 3``
``[1] 4.666667``

R allows you to add parentheses `(` `)` when you need to impose the order of operations. When it comes to raising a number to the power of another one, use the symbol `^` or `**`.

``(24 + 3) ^ (1 / 3)``
``[1] 3``
Exercise

In R, calculate:

• 25 plus 49
• 6 minus 19
• 8 multiplied by 6
• 7 divided by 2
• 9 squared
• multiply the sum of 9 and 2 by 3

### 6.1.2 Comparisons

You can compare 2 elements using the following operators:

• `>` greater than,
• `>=` greater than or equal to,
• `<` less than,
• `<=` less than or equal to,
• `==` equal to,
• `!=` not equal to.

When comparing two elements, R returns either `TRUE` or `FALSE`.

``9 == 3 * 3``
``[1] TRUE``
``5 > 4``
``[1] TRUE``
``9^2 != 9 * (3 + 6)``
``[1] FALSE``
Exercise

In R,

• Test whether 22/7 is larger than `pi`
• Test if cats are greater than dogs. Why? (remember to use quote marks)
Hint Prøv katter og hunder også

### 6.1.3 Operations with functions

More complex operations such as square root, logarithms and exponentiation shall be run using specific functions. These functions are `sqrt()`, `log()`, `exp()`, etc.

Exercise

In R, calculate

• The square root of 29
• The exponent of 29
• The natural logarithm of 29
• The base 10 logarithm of 29

You may need to look at the built-in help (Chapter 7) for some of these.

What’s next

How to get help (Chapter 7)

### Contributors

• Jonathan Soulé
• Aud Halbritter
• Richard Telford