3.5 Real numbers
In this section, we look at the real numbers, denoted R, to conclude our analysis of the typical numbers most people encounter. Let’s begin with decimals. real number number$real R`bold
3.5.1 Decimals
A decimal expression for a real number looks like decimal
- an optional minus sign,
- followed a finite number of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9,
- followed by a period, also called the decimal point,
- followed by a finite or infinite number of digits.
In many parts of the world, the decimal point is a comma instead of a period, but I use the United States and UK convention here.
You may omit the decimal point if there are no digits after the decimal point.
We usually omit trailing 0s on the right when we use the number in a general mathematical context. We may keep them when they indicate the precision of a measurement...
