Decimal Numbers
Decimal Fraction
The denominator of a decimal fraction is the unit followed by zeros.
Decimal Number
Can be expressed by a decimal fraction.
It has two parts: a whole and a decimal.
To express a decimal number as a decimal fraction, write the the number without the decimal point as the numerator and as the denominator a 1, followed by as many zeros as there are decimal places in the decimal number.
Decimal Units
They are fractions whose numerator is 1 and the denominator is a power of 10.
Rounding of Decimals
If the number of decimal units is greater than or equal to 5, increase by one number the previous decimal; otherwise, it is left it as is.
Example
2.36105 
2.4 Rounding to the tenths.
2.36105 2.36 Rounding to the hundredths.
2.36105 2,361 Rounding to the thousandths.
2.36105 2.3611 Rounding to the ten-thousandths
Truncate Decimals
To truncate a decimal to a given order leave the figures prior to that order and eliminate the others.
2.3647 2.3 Truncation to the tenths.
2.3647 2.36 Truncation to the hundredths.
2.3647 2.364 Truncation to the thousandths.
2.3647 2.3467 Truncation to the ten-thousandths
