First determine the place that will be rounded to.
· Sometimes the place will be stated: Round 3.457 to the tenths place.
· Sometimes the place will be underlined: Round 3.457 to the underlined digit.
Round to the ones place, round to the units place, and round to the nearest whole number all mean the same thing.
Underline the place that you are rounding to, the target digit. With a decimal number, the rounded answer will have no numbers to the right of the target digit.
In most cases:
· All the numbers to the left of the target stay the same.
· All the numbers to the right of the target digit are dropped off – we don’t need them and don’t write them.
· The target digit either stays the same or is increased by 1 depending on the value of the digit to the right (5 or above, the target increases by 1; below 5 the target stays the same.)
The only exception is when the target digit is a 9 and the digit to the right is 5 or greater. In this case, the target goes from 9 to 0 and the digit to left is increased by 1.
(nothing after the ones / whole number place)
(nothing after the tenths place)
(nothing after the hundredths place)
The 7 in the hundredths place means the 9 in the tenths place must increase by 1. But 9 is the highest numeral we have. So we must increase the next place, the ones place, by 1. Think of it as 10 tenths being “regrouped” into 1. So the 3 (wholes) becomes a 4 and there are 0 extra tenths.