7 (a) Work out - OCR - GCSE Maths - Question 7 - 2017 - Paper 1
Question 7
7 (a) Work out.
(i) 1 + 4 + 2
(ii) 2 + 5 × (8 - 4)
(b) Evaluate.
(i) 25
(ii) √400
(c) Estimate the value of
23.1 × 3.9
8.12
Worked Solution & Example Answer:7 (a) Work out - OCR - GCSE Maths - Question 7 - 2017 - Paper 1
(a) Work out.
(i) 1 + 4 + 2
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To solve this, add the numbers together:
1 + 4 = 5
Then, adding 2 gives:
5 + 2 = 7
Thus, the answer is 7.
(a) Work out.
(ii) 2 + 5 × (8 - 4)
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First, solve the expression inside the brackets:
8 - 4 = 4
Next, multiply 5 by the result:
5 × 4 = 20
Finally, add 2:
2 + 20 = 22
Therefore, the answer is 22.
(b) Evaluate.
(i) 25
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To evaluate 25, we recognize it as a power of 5:
25 = 5^2.
So, the answer is 25.
(b) Evaluate.
(ii) √400
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To find the square root of 400, we look for a number that when multiplied by itself equals 400:
20 × 20 = 400.
Thus, √400 = 20.
(c) Estimate the value of
23.1 × 3.9
8.12
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To estimate the value, round the numbers:
23.1 ≈ 23
3.9 ≈ 4
8.12 ≈ 8.
Now, compute the estimation:
Estimate = \frac{23 × 4}{8}.
Calculating this gives:
23 × 4 = 92,
and then:
\frac{92}{8} = 11.5.
Thus, the estimated value is approximately 11.5.
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