4th Grade Rounding Whole Numbers Worksheet Solutions (PDF)

4th Grade math worksheet solutions: Rounding Whole Numbers – Maths PDF

Use this answer key to check each rounding problem. Every solution names the rounding place, shows the digit to its right, and gives the rounded number in bold. Estimates are compared with exact answers so you can see why they are reasonable.

Grade 4 · Common Core State Standards: 4.NBT.A.3

Exercise 1 – Nearest ten

The tens digit is 8. The digit to its right is 3, which is less than 5, so keep 8.

$683$ rounds to $680$.

Exercise 2 – Nearest hundred

The hundreds digit is 2. The digit to its right is 5, so round up to 3.

$4,300$

Exercise 3 – Nearest thousand

The thousands digit is 8. The digit to its right is 7, so round up to 9.

$39,000$

Exercise 4 – Halfway number

2,500 is exactly halfway, so it rounds up to 3,000.

The number line shows 2,500 exactly halfway between 2,000 and 3,000. By the rule, halfway numbers round up.

$3,000$

Exercise 5 – Nearest ten thousand

The ten thousands digit is 7. The digit to its right is 6, so round up to 8.

$80,000$

Exercise 6 – Nearest hundred thousand

The hundred thousands digit is 4. The digit to its right is 8, so round up to 5.

$500,000$

Exercise 7 – Use the number line

347 is right of the halfway point 345, so it rounds to 350.

347 is 7 steps from 340 and 3 steps from 350, so it is closer to 350.

$350$

Exercise 8 – Rounding a 9

The tens digit is 9 and the digit to its right is 9, so round up. 9 tens plus 1 ten is 10 tens, which carries.

$990 + 10 = 1{,}000$

$1,000$

Exercise 9 – Carrying across thousands

9,960 is closer to 10,000 than to 9,900.

The hundreds digit is 9. The digit to its right is 6, so round up. 99 hundreds plus 1 hundred is 100 hundreds.

$10,000$

Exercise 10 – Another halfway number

The thousands digit is 4. The digit to its right is 5, so round up to 5.

$25,000$

Exercise 11 – Three places

Ten thousand: the digit 5 is followed by 8, so round up to $360,000$.

Thousand: the digit 8 is followed by 4, so keep it: $358,000$.

Hundred: the digit 4 is followed by 2, so keep it: $358,400$.

$360,000$; $358,000$; $358,400$

Exercise 12 – Smallest and greatest

Numbers from halfway below 700 up to just under halfway above 700 round to 700. Halfway below is 650 and halfway above is 750.

650 rounds up to 700. 749 rounds down to 700. 750 rounds up to 800.

Smallest: 650. Greatest: 749.

Exercise 13 – Estimate a sum

$4,862$ rounds to $5,000$. $2,139$ rounds to $2,000$.

$5{,}000 + 2{,}000 = 7{,}000$

about $7,000$

Exercise 14 – Estimate a difference

$52,816$ rounds to $50,000$. $19,374$ rounds to $20,000$.

$50{,}000 – 20{,}000 = 30{,}000$

about $30,000$

Exercise 15 – Stadium crowd

Thousand: the 8 is followed by 7, so round up to 19: $19,000$.

Hundred: the 7 is followed by 4, so keep it: $18,700$.

$19,000$; $18,700$

Exercise 16 – Road trip estimate

$1,286$ rounds to $1,300$. $874$ rounds to $900$.

Estimate: $1{,}300 + 900 = 2{,}200$.

Exact: $1{,}286 + 874 = 2{,}160$.

The difference is only 40 miles, so the exact answer is reasonable.

Estimate $2,200$ miles; exact $2,160$ miles

Exercise 17 – Fundraiser change

$\$3,482.00$ rounds to $\$3,500.00$. $\$2,961.00$ rounds to $\$3,000.00$.

Estimate: $3{,}500 – 3{,}000 = 500$.

Exact: $3{,}482 – 2{,}961 = 521$.

about $\$500.00$ more; exactly $\$521.00$ more

Exercise 18 – Could it be the number?

A number rounds to $40,000$ when it is from $35,000$ up to $44,999$.

35,999 is in the range (round up from 35,000). 38,420 is in the range. 44,100 is in the range. 45,000 rounds up to 50,000, so it is not.

35,999, 38,420, and 44,100

Exercise 19 – Is $5,000 enough?

Nearest thousand: $2{,}000 + 2{,}000 + 1{,}000 = 5{,}000$. This estimate says she has exactly enough, which is not helpful.

Nearest hundred: $1{,}900 + 2{,}200 + 1{,}100 = 5{,}200$. This estimate says she does not have enough.

Exact: $1{,}879 + 2{,}246 + 1{,}125 = 5{,}250$.

Since $\$5,250.00$ is more than $\$5,000.00$, she is short by $\$250.00$. The hundreds estimate is more useful.

Nearest hundred; exact total $\$5,250.00$

Exercise 20 – Find the mistake

The tens digit is 9. The digit to its right is 5, which is 5 or more, so the 9 must round up. Liam kept it instead.

Correct: $6{,}490 + 10 = 6{,}500$, so $6,495$ rounds to $6,500$.

Nearest hundred: the hundreds digit is 4 and the digit to its right is 9, so round up to $6,500$.

$6,500$ for both

All Grade 4 chapters: Grade 4 math.

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