At its core, R is a very fancy calculator. We can place spaces around an operator, such as the addition operator, there's no need for an equal sign. By pressing enter, we can see the output of three on the screen. The spaces are not mandatory, however, they are best practice to help readability. One divided by four returns 0.25 The trailing zeros are suppressed as you would expect in a calculator, one divided by three, or one, space, divided by three, for readability. The default for this is, seven digits are displayed. 

The carrot symbol, is the exponential operator, in terms of the order of precedents, or the order of operations, in this formula here, we have the exponential first, followed by division, then addition. Raising 16 to the power, a half, and I will use brackets here to enforce parenthesis to be run first, returns four, that's the same as taking the square root of 16, large numbers are notated by scientific notation. If I write down 1e6 I'm asking for 10 to the power of six, but if I was to take that number, divide it by four, raise it to the power, a half, without any parenthesis, the order of precedents in R, differs from that, the order of precedence in mathematics.