Explanation:
The dot is called a decimal point. It is also called the decimal separator. It separates whole numbers from fractional numbers.
In this example;
24.671
The numbers before the point, 24 is the whole number
The numbers after the point, 671 are the fractional portion of the number. They represent 6 tenths, 7 hundredths and 1 thousandths.
Also, the number of digits after the point tells you how many decimal place the number is in. In this example the number of decimal places is 3.