High School

Round off to the nearest whole number:

3.1, 3.65, 14.452, 1.768, 39.1

Round off to 1 decimal place:

19.47, 6.77, 489.99, 421.34

Answer :

To round numbers to the nearest whole number or to one decimal place, you follow a simple set of rules. Let me explain these steps for each part of your question.

Rounding to the Nearest Whole Number

  1. 3.1

    • Look at the digit in the tenths place (the first digit to the right of the decimal point). Here, it is 1.
    • If this digit is less than 5, round down. So, 3.1 becomes 3.

  2. 3.65

    • The tenths place is 6.
    • Since 6 is 5 or more, round up. So, 3.65 becomes 4.

  3. 14.452

    • The tenths place here is 4.
    • As 4 is less than 5, round down. 14.452 becomes 14.

  4. 1.768

    • The tenths place is 7.
    • Since 7 is more than 5, round up. So, 1.768 becomes 2.

  5. 39.1

    • The tenths place is 1.
    • Since 1 is less than 5, round down. 39.1 becomes 39.

Rounding to One Decimal Place

  1. 19.47

    • Look at the hundredths place (the second digit to the right of the decimal point). Here, it is 7.
    • Since 7 is 5 or more, round up the tenths place from 4 to 5. So, 19.47 becomes 19.5.

  2. 6.77

    • The hundredths place is 7.
    • Round up the tenths place from 7 to 8. So, 6.77 becomes 6.8.

  3. 489.99

    • The hundredths place is 9.
    • Round up the tenths place from 9 to 10, which adds 1 to the units digit. So, 489.99 becomes 490.0.

  4. 421.34

    • The hundredths place is 4.
    • Since 4 is less than 5, round down and keep the tenths digit as 3. So, 421.34 becomes 421.3.

Rounding numbers helps simplify them while keeping them approximately the same, which is useful for estimation and mental calculations.

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