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(a) Write 4.5 × 10² as an ordinary number - Edexcel - GCSE Maths - Question 4 - 2021 - Paper 3

Question 4

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(a) Write 4.5 × 10² as an ordinary number.
(b) Write 0.007 in standard form.
(c) Work out 4.2 × 10² + 5.3 × 10¹
Give your answer in standard form.
Worked Solution & Example Answer:3
(a) Write 4.5 × 10² as an ordinary number - Edexcel - GCSE Maths - Question 4 - 2021 - Paper 3
(a) Write 4.5 × 10² as an ordinary number.

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To convert 4.5 × 10² into an ordinary number, we need to multiply 4.5 by 100 (which is 102). This gives us:
4.5×100=450.
Thus, 4.5 × 10² as an ordinary number is 450.
(b) Write 0.007 in standard form.

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To express 0.007 in standard form, we recognize that it can be written as:
7×10−3
This shows 0.007 in standard form as 7×10−3.
(c) Work out 4.2 × 10² + 5.3 × 10¹
Give your answer in standard form.

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To sum the two values, we first align them in standard form:
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Convert 5.3 × 10¹ into a comparable format by rewriting it as 0.53 × 10²:
5.3×101=0.53×102
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Now we can add:
4.2×102+0.53×102=(4.2+0.53)×102=4.73×102
Thus, in standard form, the result of the addition is 4.73×102.
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