Subtracting numbers in standard form | Maths | Quizalize & Oak National Academy

Starter quiz

Match each number in standard form to its equivalent ordinary number.

$7.5\times10^{-4}$

⇔

0.00075 ✓

$5.7\times10^{4}$

⇔

57000 ✓

$5.5\times10^{4}$

⇔

55000 ✓

$5.7\times10^{8}$

⇔

570000000 ✓

$7\times10^{4}$

⇔

70000 ✓
Without a calculator, work out 3.42 – 1.23.

'2.19' ✓
Without a calculator, work out 28.48 – 3.203.

'25.277' ✓
Without a calculator, work out 12.4 – 2.42 + 4.64.

'14.62' ✓
$5^3 – 5^2 + \sqrt{25}$ = ______

'105' ✓
Match each number to a correct statement about that number.

$-9\times10^2$

⇔

is negative ✓

$9\times10^2$

⇔

is positive and less than 1000 ✓

$9\times10^{-2}$

⇔

is less than 1 ✓

$2\times10^{9}$

⇔

is even and greater than 1000 ✓

Exit quiz

Work out $9.8\times10^5 - 6.8\times10^5$ , giving your answer in standard form.

$3\times10^5$ ✓

$3\times10^7$

$3\times10^{9}$

$3\times10^{10}$
Work out $3\times10^{-8} - 1.8\times10^{-8}$ , giving your answer in standard form.

$1.2\times10^{-16}$

$1.2\times10^{-9}$

$1.2\times10^{-8}$ ✓

$1.2\times10^{0}$
Work out $2.4\times10^7 - 3\text{ } 700\text{ }000$ , giving your answer in standard form.

$2.03\times10^4$

$2.03\times10^7$ ✓

$2.03\times10^9$

$2.03\times10^{11}$
Work out $4.9\times10^6- 280\text{ }000$ , giving your answer in standard form.

$4.62\times10^2$

$4.62\times10^3$

$4.62\times10^4$

$4.62\times10^5$

$4.62\times10^6$ ✓
Work out $9.38 \times 10^{10} - 1 \text{ } 300 \text{ } 000 \text{ } 000$ . Give your answer in standard form.

$92.5\times10^{10}$

$9.25\times10^{10}$ ✓

$0.925\times10^{9}$

$92.5\times10^{9}$

$9.25\times10^{9}$
$9$ mm − $0.5$ cm − $2\times10^{-3}$ m = ______ metres.

$2\times10^{-4}$ m

$3\times10^{-3}$ m

$2\times10^{-3}$ m ✓

$3\times10^{-4}$ m

$1\times10^{-3}$ m

Worksheet

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Lesson Details

Key learning points

When subtracting numbers represented in standard form, place value is an important consideration.
If the power of 10 is the same for both numbers, it is easy to subtract.
Standard form calculations can be done using a calculator.

Common misconception

When subtracting numbers in standard form, pupils can also add the exponents of 10.

The use of the place value chart shows how the magnitude does not change to the sum of the powers of 10. The place value chart can support pupils to make the correct addition or subtraction of large or small numbers.

Keywords

Standard form - Standard form - Standard form is when a number is written in the form A × 10^n, (where 1 ≤ A < 10 and n is an integer).