Remember this whenever rounding. If the digit before you are rounding to is less than 5, you ALWAYS round down. If it is 5 or greater, you ALWAYS round up.
In 5.193,
5 represents the ones
5.1 represents the ones in the tenths column
5.19 represents the ones in the hundredths column
5.193 represent the ones in the thousandths column
The first place value after the decimal point is called the tenths place. The second place value after the decimal point is called the hundredths place. To round, remember that you take the place value after the one that it is asking for and numbers 5 and up round up, numbers 4 and below round down. Hope this helps :)
