ROUND OFF TO ONE AND TWO SIGNIFICANT FIGURES

Rounding Off to One Significant Figure

To round off the number to the significant figures, we follow the steps given below.

Rounding Off to Two Significant Figures

To round off the number to the significant figures, we follow the steps given below.

Round off to one significant figure:

Problem 1 :

69

Solution:

69

In 69, the digit after the one significant figure is 9.

9 ≥ 5

So, 69 to one significant figures = 70.

Problem 2 :

197

Solution:

197

In 197, the digit after the one significant figure is 9.

9 ≥ 5

So, 197 to one significant figures = 200.

Problem 3 :

293

Solution:

293

In 293, the digit after the one significant figure is 9.

9 ≥ 5

So, 293 to one significant figures = 300.

Problem 4 :

347

Solution:

347

In 347, the digit after the one significant figure is 4.

4 ≥ 5

The above statement is false. So, 347 to one significant figures = 300.

Problem 5 :

963

Solution:

963

In 963, the digit after the one significant figure is 6.

6 ≥ 5

So, 963 to one significant figures = 1000.

Problem 6 :

2555

Solution:

2555

In 2555, the digit after the one significant figure is 5.

5 ≥ 5

So, 2555 to one significant figures = 3000.

Problem 7 :

6734

Solution:

6734

In 6734, the digit after the one significant figure is 7.

7 ≥ 5

So, 6734 to one significant figures = 7000.

Problem 8 :

39500

Solution:

39500

In 39500, the digit after the one significant figure is 9.

9 ≥ 5

So, 39500 to one significant figures = 40000.

More on rounding off to two significant figures :

Round off to two significant figures:

Problem 1 :

891

Solution:

891

In 891, the digit after the two significant figure is 1.

1 ≥ 5

The above statement is false. So, 891 to two significant figures = 890.

Problem 2 :

166

Solution:

166

In 166, the digit after the two significant figure is 6.

6 ≥ 5

So, 166 to two significant figures = 170.

Problem 3 :

750

Solution:

750

In 750, the digit after the two significant figure is 0.

0 ≥ 5

The above statement is false. So, 750 to two significant figures = 750.

Problem 4 :

238

Solution:

238

In 238, the digit after the two significant figure is 6.

8 ≥ 5

So, 238 to two significant figures = 240.

Problem 5 :

561

Solution:

561

In 561, the digit after the two significant figure is 1.

1 ≥ 5

The above statement is false. So, 561 to two significant figures = 560.

Problem 6 :

5647

Solution:

5647

In 5647, the digit after the two significant figure is 4.

4 ≥ 5

The above statement is false. So, 5647 to two significant figures = 5600.

Problem 7 :

9750

Solution:

9750

In 9750, the digit after the two significant figure is 5.

5 ≥ 5

So, 9750 to two significant figures = 9800.

Problem 8 :

23501

Solution:

23501

In 23501, the digit after the two significant figure is 5.

5 ≥ 5

So, 23501 to two significant figures = 24000.

Round off to the accuracy given:

Problem 9 :

€35246 (to the nearest €1000)

Solution:

35246

To round off a number to its nearest thousand we check the last three digits of the number.

2 ≥ 5

The above statement is false. So, €35246 when rounded off to the nearest thousand is €35000.

Problem 10 :

a distance of 3651 km (to the nearest 100 km)

Solution:

3651

To round off a number to its nearest hundred we check the last two digits of the number.

5 ≥ 5

So, 3651 km when rounded off to the nearest hundred is 3700 km.

Problem 11 :

a donation of $375 (to one significant figure)

Solution:

375

In 375, the digit after the one significant figure is 7.

7 ≥ 5

So, $375 to one significant figures = $400.

Problem 12 :

a house sold for £237629 (to the nearest £10000)

Solution:

237629

To round off a number to its nearest ten thousand we check the last four digits of the number.

7 ≥ 5

So, £237629 when rounded off to the nearest ten thousand is £240000.

Problem 13 :

the attendance at a rock concert is 16723 (to the nearest thousand)

Solution:

16723

To round off a number to its nearest thousand we check the last three digits of the number.

7 ≥ 5

So, 16723 when rounded off to the nearest thousand is 17000.

Problem 14 :

the crowd is 35381 people (to two significant figures)

Solution:

35381

In 35381, the digit after the two significant figure is 3.

3 ≥ 5

The above statement is false. So, 35381 to two significant figures = 35000.