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Mathematics for IGCSE & O level - Estimation (Section 3)

1
What is 3.1 x 1.9 (correct to 1 s.f.)?
Answer
(B)
7
2
What is the approximate value for 52417 rounded to 2 significant figures?
Answer
(B)
53,000
3
When estimating the area of a rectangle, the length is 17.1cm and the width is 6.3 cm. What is the estimated area?
Answer
(A)
100 cm²
4
When you have to round to the nearest 2 d.p., what are the digits you need to consider?
Answer
(C)
The third digit
5
What is a common mistake when rounding to a given number of significant figures?
Answer
(C)
Counting the wrong number of zeros.
6
What is the first step in estimating the cost of 24 golf balls at $5.75 each?
Answer
(B)
Round $5.75 to one significant figure.
7
If the digit to the right of the desired place to round to is less than 5, how do you round?
Answer
(B)
Round down
8
What is the answer for 99/4.6 to 1 significant figure?
Answer
(B)
10
9
What is 1.5736 rounded to 2 decimal places?
Answer
(B)
1.58
10
When can you use estimation?
Answer
A
B
D
11
What is 3.520 to 1 decimal place?
Answer
(B)
3.6
12
What does 'd.p.' stand for?
Answer
(C)
Decimal places
13
How many significant figures does the number 100 have?
Answer
(B)
2
14
How should you express your answer when you have rounded numbers in a calculation?
Answer
(D)
State the accuracy of your answer when you have rounded them.
15
Which of the following are important when estimating answers to problems?
Answer
A
C
D
16
What does it mean for a digit to be 'significant'?
Answer
(C)
The digit contributes to the value of the number.
17
Which of the following statements is true about estimation?
Answer
(B)
It involves simplifying a calculation to find an approximate answer.
18
Which of the following is NOT an example of estimation?
Answer
(B)
Using a calculator to find an answer.
19
What is 17100 rounded to 1 s.f.?
Answer
(C)
20000
20
What does it mean to 'estimate' an answer to a problem?
Answer
(C)
To find an approximate answer using simpler calculations.
21
In which situation might estimation be the preferred method for a calculation?
Answer
(B)
When you need a quick answer and precision is not critical.
22
When rounding 8.478 to 1 d.p., what is the result?
Answer
(C)
8.6
23
What should the approximation of the value 16.56 / 2.28 be?
Answer
(B)
7
24
What is the approximate value of 19.89 to 1 significant figure?
Answer
(C)
20
25
When are zeros significant?
Answer
B
C
D
26
What is the general method to estimate answers to problems?
Answer
(A)
Round each number to one significant figure and perform the calculation.
27
What would be a suitable degree of accuracy for giving the value of a table’s length and width measurement?
Answer
(B)
Round to the same accuracy as the original measurements.
28
What are leading zeros?
Answer
(C)
Zeros at the beginning of a decimal number.
29
Which number is used to maintain the place value of the digit when we want to round?
Answer
(A)
Zero
30
If a number is 3.874, which digit dictates what it rounds to when rounding to 2 significant figures?
Answer
(D)
4
31
What are the key points to remember about significant figures?
Answer
A
B
C
D
32
When rounding to a given number of decimal places, what should you look at?
Answer
(B)
The digit immediately to the right of the desired decimal place.
33
What is the first non-zero digit in the number 0.0056?
Answer
(B)
5
34
When rounding numbers to estimate a square root, which of the following should you do?
Answer
(C)
Round to the nearest perfect square.
35
What is an example of estimation?
Answer
(B)
Rounding a number to one significant figure before performing a calculation.
36
In a calculation, if one of the values is accurate to 1 decimal place, to what degree of accuracy should you express the answer?
Answer
(B)
To 1 decimal place.
37
When rounding to 1 d.p., what do you look at?
Answer
(A)
The second digit after the decimal point
38
When rounding to 1 s.f., how many digits are kept?
Answer
(A)
1
39
When you are rounding a number, which side are you using?
Answer
(B)
Right side
40
What is 126 rounded to 1 s.f.?
Answer
(B)
120
41
What is the most significant digit in the number 0.00456?
Answer
(B)
4
42
What is one reason to round numbers to one significant figure when estimating the answer to a problem?
Answer
(A)
To make the calculation simpler.
43
What is 7.0666 rounded to 2 decimal places?
Answer
(B)
7.07
44
What is the approximate value for 0.71*sqrt(162)?
Answer
(B)
10
45
Which of the following is a good reason to use estimation?
Answer
(A)
To get a quick approximate answer.
46
What are the steps to estimate the result of a calculation, rounding to 1 significant figure?
Answer
(B)
Round each number to 1 significant figure, then perform the calculation.
47
What is the meaning of 1 s.f.?
Answer
(A)
1 significant figure
48
Estimate 4.7 * 1.9
Answer
(A)
8
49
What do you call the places to the right of the decimal point?
Answer
(B)
Decimal places
50
When rounding to a given number of decimal places, you look at the digit to the _?
Answer
(B)
right