HOW TO ROUND DECIMALS TO THE NEAREST THOUSANDTH

Example 1 :

Round 5.2648 to the nearest thousandth.

Answer :

Underline 4, the digit at thousandths place.

5.2648

The digit to the right of the underlined digit is 8, which is greater than 5.

Then, add 1 to the digit 4 at thousandths place and drop the digit 8 to the right of 4.

Therefore, 5.2648 rounded to the nearest thousandths is 5.265.

Example 2 :

Round 1.35425 to the nearest thousandth.

Answer :

Underline 4, the digit at thousandths place.

1.35425

The digit to the right of the underlined digit is 2, which is less than 5.

Then, keep the digit 4 at thousandths place as it is and drop all the digits to the right of 4.

Therefore, 1.35425 rounded to the nearest thousandth is 1.354.

Example 3 :

Round 7.5509 to the nearest thousandth.

Answer :

Underline 0, the digit at thousandth place.

7.5509

The digit to the right of the underlined digit is 9, which is greater than 5.

Then, add 1 to the digit 0 at thousandths place and drop the digit 9 to the right of 0.

Therefore, 7.5509 rounded to the nearest thousandth is 7.551.

Example 4 :

Round 5.42978 to the nearest thousandth.

Answer :

Underline 9, the digit at thousandths place.

5.42978

The digit to the right of the underlined digit is 7, which is greater than 5.

Then, add 1 to the digit 9 at thousandths place and drop all the digits to the right of 9.

Therefore, 5.42978 rounded to the nearest thousandth is 5.430.

Examples 5-6 : Round each of the following numbers to the nearest thousandth :

Example 5 :

Answer :

In 5.3849, the digit at thousandths place is 4.

The digit to the right of 4 is 9, which is greater than 5.

Then, add 1 to the digit 4 at thousandths place and drop the digit 9 to the right of 4.

Therefore, 5.3849 rounded to the nearest thousandth is 5.385.

Example 6 :

Answer :

In 3.4234, the digit at thousandths place is 3.

The digit to the right of 3 is 4, which is less than 5.

Then, keep the digit 3 at thousandths place as it is and drop the digit 4 to the right of 3.

Therefore, 3.4234 rounded to the nearest thousandth is 3.423.

Example 7 :

Find the circumference of the circle whose radius is 8 cm. Use the value of π from your calculator and round your answer to the nearest thousandth.

Answer :

Formula for circumference of a circle :

= 2πr

Substitute r = 8.

= 2π(8)

= 16π

Using calculator for the the value of π,

= 50.26548........

Underline 5, the digit at thousandths place.

= 50.26548........

The digit to the right of the underlined digit is 4, which is less than 5.

Then, keep the digit 5 at thousandths place and drop all the digits to the right of 5.

50.26548........ rounded to the nearest thousandth is 50.265.

Therefore, the circumference of the circle is about 50.265 cm.

Example 8 :

Find the area of the circle whose radius is 12 cm. Use the value of π from your calculator and round your answer to the nearest thousandth.

Answer :

Formula for area of a circle :

= πr²

Substitute r = 12.

= π(12)²

= 144π

Using calculator for the the value of π,

= 452.3893........

Underline 9, the digit at thousandths place.

= 452.3893........

The digit to the right of the underlined digit is 3, which is less than 5.

Then, keep the digit 9 at thousandths place as it is and drop all the digits to the right of 9.

452.3893........ rounded to the nearest thousandth is 452.389.

Therefore, the area of the circle is about 452.389 cm².

Example 9 :

Benjamin has been asked to round 1.4725 to the nearest thousandth. His answer is 14.725 Explain Daniel’s mistake and what is the correct answer?.

Answer :

Instead of rounding to the nearest thousandth, Daniel has moved the decimal place.

The correct answer is 1.473.

Example 10 :

Olivia has rounded a number to the nearest thousandth and her answer was 8.527. Write down 10 different possible numbers that she could have rounded.

Answer :

8.5265

8.5266

8.5267

8.5268

8.5269

8.5270

8.5271

8.5272

8.5273

8.5274

Practice Questions

Click here to get detailed answers for the above questions.

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.