Edexcel IGCSE Math A Foundation 1.9 Standard Form Questions

Use standard-form questions to convert ordinary numbers, calculate with powers of 10 and keep final answers in correct form.

Exam points

Convert ordinary numbers and standard-form values in both directions accurately.
Calculate with powers of 10, then rewrite the answer so the coefficient is 1 ≤ a < 10.
Interpret contextual standard-form comparisons involving large or small quantities.

Covered syllabus points

1.9.A Standard form

[Maximum number: 3]

(a)

Write $5.76 \times 10^{4}$ as an ordinary number.

[ 1 ]

(b)

Work out $\frac{3 \times 10^{5}+8 \times 10^{3}}{4 \times 10^{-2}}$

Give your answer in standard form.

[ 2 ]

Working:
$\frac{3\times10^5+8\times10^3}{4\times10^{-2}} =\frac{308000}{0.04} =7700000$

Final answer:
$7.7\times10^6$

M1 for a correct intermediate expression or 7700000, $77\times10^5$ , or $7.7\times10^n$ with $n\ne6$ . A1 for $7.7\times10^6$ .

[Maximum number: 4]

(a)

Write $6.04 \times 10^{5}$ as an ordinary number.

[ 1 ]

$6.04\times10^{5}=604000$

Final answer:
604000

(b)

Write 0.00007 in standard form.

[ 1 ]

$0.00007=7\times10^{-5}$

Final answer:
$7\times10^{-5}$

(c)

Work out $\frac{7.6 \times 10^{10}}{4 \times 10^{5}-2 \times 10^{4}}$

Give your answer in standard form.

[ 2 ]

Official intermediate value:
$3.8\times10^{5}$

Final answer:
$2\times10^{5}$

Accept $2.0\times10^{5}$ or $2.00\times10^{5}$ .

SC B1 for 200000, $20\times10^{4}$ , $0.2\times10^{6}$ , or $2\times10^{n}$ where $n\ne5$ , when given as a final answer.

[Maximum number: 4]

(a)

Write 520 million in standard form.

[ 1 ]

$520\text{ million}=520000000=5.2\times 10^{8}$

Final answer:
$5.2\times 10^{8}$

(b)

Write $8.79 \times 10^{-5}$ as an ordinary number.

[ 1 ]

$8.79\times10^{-5}=0.0000879$

Final answer:
0.0000879

(c)

Work out $\left(5 \times 10^{42}\right) \times\left(7 \times 10^{-180}\right)$

Give your answer in standard form.

[ 2 ]

$(5\times10^{42})(7\times10^{-180}) = 35\times10^{-138}$ $35\times10^{-138} = 3.5\times10^{-137}$

Final answer:
$3.5\times10^{-137}$

All question bank results loaded

Covered syllabus points

Question 1

Question (a)

Question (b)

Question 2

Question (a)

Question (b)

Question (c)

Question 3

Question (a)

Question (b)

Question (c)