When used as verbs, round down means to round (a number) to the greatest integer that is not greater than it, or to some other lower value, especially a whole number of hundreds, thousands, etc, whereas truncate means to shorten (something) by, or as if by, cutting part of it off.

What is truncating and rounding?

Round computes the nearest number to the input to a specified degree of accuracy. Rounds a value to the nearest integer or to the specified number of fractional digits. Math. Truncate effectively discards the any digits after the decimal point. It will always round to the nearest integer toward zero.

Does truncated mean rounded?

When we truncate a number, we find an estimate for the number without doing any rounding. To truncate a number to 2 decimal places, miss off all the digits after the second decimal place. ...