Write (4 × 10^5) × (3 × 10^-3) in standard form.

Worked solution for TMUA-P1-MNUM-007 is revealed on this page behind the solution details.

Why isn't the answer to TMUA-P1-MNUM-007 shown upfront?

The options are lettered without marking the correct one so you attempt TMUA-P1-MNUM-007 first — TMUA questions reward spotting the trap before you check the worked solution below.

Do I need a calculator for TMUA-P1-MNUM-007?

No — calculators are banned in the TMUA. TMUA-P1-MNUM-007 is set for a no-calculator target of about 180 seconds; the worked solution shows the fastest by-hand route.

Which TMUA specification point is TMUA-P1-MNUM-007?

TMUA-P1-MNUM-007 is Paper P1 · Number (specification code M-Num), level 2. Drill more of the same topic from this page.

TMUA-P1-MNUM-007 — Paper P1 · Number · Level 2

P1M-NumLevel 2~180s target

Spec: M-Num · No calculator · ~180s

Write

(4 \times 10^5) \times (3 \times 10^{-3})

in standard form.

Options

$12 \times 10^{2}$
$1.2 \times 10^{3}$
$7 \times 10^{2}$
$1.2 \times 10^{8}$
$12 \times 10^{8}$

Letters only — the answer key is hidden. Work it out, then check the solution below.

Hint (check trope)

No written hint yet — check the trope: standard-form-calc, normalisation-trap. Name the trap first, work the stem by hand, then open the solution below.

Show solution

Multiply:

4 \times 3 = 12

and

10^5 \times 10^{-3} = 10^2

, giving

12 \times 10^2 = 1.2 \times 10^3

. Trap:

12 \times 10^2

is numerically right but not standard form — plausible if you stop before normalising.

Keep practising

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P1M-NumLevel 2
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Write 6 × 10^42 × 10^-2 in standard form.
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Step up a level
P1M-NumLevel 3
TMUA-P1-MNUM-011
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Keep practising

Same topic · same level

P1M-NumLevel 2

TMUA-P1-MNUM-005

What is the lowest common multiple (LCM) of 12, 18 and 20?

Number

Open TMUA-P1-MNUM-005 →

Same trap: standard-form-calc

P1M-NumLevel 2

TMUA-P1-MNUM-042

Write 6 × 10^42 × 10^-2 in standard form.

Number

Open TMUA-P1-MNUM-042 →

Step up a level

P1M-NumLevel 3

TMUA-P1-MNUM-011

4000 is invested. It grows by 5\% in year one, then falls by 5\% in year two. What is its final value?

Number

Open TMUA-P1-MNUM-011 →

TMUA-P1-MNUM-007 — Paper P1 · Number · Level 2

Options

Keep practising

Master Number

TMUA-P1-MNUM-007 — Paper P1 · Number · Level 2

Options

Keep practising

Master Number