Numbers and place value · Ages 10–11
Rounding and estimating large numbers worksheet
Part of: Large numbers and other numerals
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Rounding and estimating large numbers worksheet
Numbers and place value · Ages 10–11
Numsprite
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Name:Date:Score:／48
Write each answer in the space. For word problems, show your working and write a sentence answer.
Part A: Working out and filling in (2 marks each)
1.Round 41,573,481 to the nearest ten thousand. About how many times 10,000 is it?
Answer:
2.Round 29,207 to the nearest ten thousand. About how many times 10,000 is it?
Answer:
3.Round 43,268 to the nearest ten thousand. About how many times 10,000 is it?
Answer:
4.Round 4,601,903,769 to the nearest hundred million. About how many times 100,000,000 is it?
Answer:
5.A photo of a huge crowd is split into 40 equal squares. One square has about 34 people. About how many people are in the photo?
Answer:
6.56,627,000 = × 10,000
Answer:
7.55,928,000 = × 10,000
Answer:
8.A photo of a huge crowd is split into 60 equal squares. One square has about 83 people. About how many people are in the photo?
Answer:
Part B: Choose, or true or false (2 marks each)
9.Round 73,253,558 to the nearest hundred thousand. Which is the result?
- A. 73,200,000
- B. 73,300,000
- C. 73,250,000
- D. 73,000,000
Choose the right answer
Answer:
10.Round 2,159,002 to the nearest hundred thousand. Which is the result?
- A. 2,100,000
- B. 2,000,000
- C. 2,160,000
- D. 2,200,000
Choose the right answer
Answer:
11.100 sheets of paper make a pile about 1 cm thick. A pile is about 54 cm high. About how many sheets is it?
- A. 540
- B. 154
- C. 54,000
- D. 5,400
Choose the right answer
Answer:
12.594,915,372 rounded to the nearest ten million is 590,000,000.
True or false?
Answer:
Part C: Word problems (4 marks each)
13.Visitors spent $20,822,718,788 in a region last year. About how many times $100,000,000 is that, to one decimal place?
Working:
Answer:
14.A dictionary has about 1,100 pages, and one page has about 1,500 words. About how many words are in the dictionary?
Working:
Answer:
15.May marks out 1 square metre of lawn and counts about 900 blades of grass. The whole lawn is about 2,100 square metres. About how many times 10,000 blades are there?
Working:
Answer:
16.The organisers say about 38 × 10,000 people came today (rounded to the nearest ten thousand). What is the most that could really have come?
Working:
Answer:
17.A run of concerts drew 904,220 people. A newspaper rounds the figure to the nearest ten thousand. About how many times 10,000 people is that?
Working:
Answer:
18.Visitors spent $85,633,826,206 in a region last year. About how many times $100,000,000 is that, to one decimal place?
Working:
Answer:
Show the answers and working
Rounding and estimating large numbers worksheet: Answers and working
Part A: Working out and filling in
1. 4,157 × 10,000
To the nearest ten thousand, look only at the thousands digit of 41,573,481. What is it?
Look at the thousands digit, 3: 0–4 rounds down, 5–9 adds 1 to the ten thousands. So it is about 4157 × 10,000.
2. 3 × 10,000
29,207 has five digits. To the nearest ten thousand, look only at the thousands digit.
Look at the thousands digit, 9: 0–4 rounds down, 5–9 adds 1 to the ten thousands. So it is about 3 × 10,000.
3. 4 × 10,000
43,268 has five digits. To the nearest ten thousand, look only at the thousands digit.
Look at the thousands digit, 3: 0–4 rounds down, 5–9 adds 1 to the ten thousands. So it is about 4 × 10,000.
4. 46 × 100,000,000
To the nearest hundred million, look only at the ten millions digit of 4,601,903,769. What is it?
Look at the ten millions digit, 0: 0–4 down, 5–9 up. About 46 × 100,000,000.
5. 1360 people
One square has about 34 people and there are 40 squares, each about the same. How can you work out the total?
About 34 a square, 40 squares: 34 × 40 = 1360.
6. 5,662.7
How many lots of 10,000 are in 56,627,000? Think how the decimal point moves when you divide by 10,000.
56,627,000 ÷ 10,000 = 5662.7, so 56,627,000 = 5662.7 × 10,000.
7. 5,592.8
How many lots of 10,000 are in 55,928,000? Think how the decimal point moves when you divide by 10,000.
55,928,000 ÷ 10,000 = 5592.8, so 55,928,000 = 5592.8 × 10,000.
8. 4980 people
One square has about 83 people and there are 60 squares, each about the same. How can you work out the total?
About 83 a square, 60 squares: 83 × 60 = 4980.
Part B: Choose, or true or false
9. B. 73,300,000
To the nearest hundred thousand, look only at the ten thousands digit of 73,253,558. What is it?
Look at the ten thousands digit: 5 ≥ 5, so add 1 to the hundred thousands and zero the rest: 73,300,000.
10. D. 2,200,000
To the nearest hundred thousand, look only at the ten thousands digit of 2,159,002. What is it?
Look at the ten thousands digit: 5 ≥ 5, so add 1 to the hundred thousands and zero the rest: 2,200,000.
11. D. 5,400
Each centimetre is about 100 sheets. How many centimetres are in 54 cm?
1 cm is about 100 sheets, so 54 cm is about 54 × 100 = 5,400.
12. True
Look at the millions digit of 594,915,372, round it yourself, then compare with 590,000,000.
Look at the millions digit, 4: rounded, it is 590,000,000.
Part C: Word problems
Marking: 2 for the working, 1 for the answer, 1 for the sentence.
13. 208.2 × $100,000,000
Divide 20,822,718,788 by 100,000,000 first, then round to one decimal place.
Divide by 100,000,000; one decimal place keeps the ten millions, rounding on the millions: about 208.2 × $100,000,000.
14. 1,650,000 words
About 1,500 words a page and about 1,100 pages, each page much the same. How can you estimate the total?
About 1,500 a page, 1,100 pages: 1,500 × 1,100 = 1,650,000.
15. 189 × 10,000
About 900 blades a square metre and 2,100 square metres. Estimate the total first, then count it in 10,000s.
900 × 2,100 blades, then ÷ 10,000: 189 × 10,000.
16. 384,999 people
Which numbers round to 38 × 10,000? What is the biggest thousands digit that still rounds down?
A thousands digit of 5 or more would round up past 38 × 10,000, so the most is the biggest with a 4 there: 384,999.
17. 90 × 10,000
To the nearest ten thousand, look at the thousands digit of 904,220.
The thousands digit is 4: to the nearest ten thousand, about 90 × 10,000.
18. 856.3 × $100,000,000
Divide 85,633,826,206 by 100,000,000 first, then round to one decimal place.
Divide by 100,000,000; one decimal place keeps the ten millions, rounding on the millions: about 856.3 × $100,000,000.
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