# Lesson Worksheet: Estimating Sums Mathematics

In this worksheet, we will practice estimating the sum of two three-digit numbers.

**Q1: **

Look at how Naser estimated the sum.

Estimate the sum of by rounding both numbers first to the nearest hundred.

Estimate the sum of by rounding both numbers first to the nearest hundred.

**Q2: **

Look at how Alanoud rounded to estimate this sum.

Round the numbers in this sum to the nearest ten.

- A
- B
- C
- D

Calculate the estimate.

**Q3: **

Look at this calculation.

Estimate the answer by rounding both numbers to the nearest hundred.

Estimate the answer by rounding both numbers to the nearest ten.

Find the exact answer.

*Tip: Use the estimates to see if your answer is sensible*.

**Q4: **

Look at how Nouf estimated this sum.

Estimate the sum of by rounding both numbers to the nearest ten.

Estimate the sum of by rounding both numbers to the nearest ten.

**Q5: **

Look at how Abdullah rounded to estimate this sum.

Round the numbers in this sum to the nearest hundred.

- A
- B
- C
- D

Calculate the estimate.

**Q6: **

Alanoud won 586 tickets at the fair. Her sister won 379.

Pick the best estimate for the total number of tickets that they won.

- A800
- B1 000
- C200
- D900
- E600

**Q7: **

Choose the number that is closest to .

*Hint*: Use rounding to help.

- A600
- B500
- C400

**Q8: **

Choose the number that is closest to , using rounding to the nearest tens.

**Q9: **

Noura is estimating the sum of 628 and 177 by rounding the numbers to the nearest hundred.

She rounds 628 to 600 and 177 to 200.

What is her estimated sum?

**Q10: **

Joury rounded 425 and 276 to their highest place values and added them together.

She got 700.

What did she round 425 to?

What did she round 276 to?