在 2010 年，联合王国的人口为 $6.3 \times 10^7$。

1. Express both populations using the same power of 10 and subtract the coefficients.

$6.3 \times 10^7 - 4.7 \times 10^6 = 6.3 \times 10^7 - 0.47 \times 10^7$
$= (6.3 - 0.47) \times 10^7$

2. Calculate the difference and state it in standard form to 2 decimal places.

$(6.3 - 0.47) \times 10^7 = 5.83 \times 10^7$
This is already in standard form since $1 \leqslant 5.83 < 10$.

1. Find the cost of one litre of petrol in the United Kingdom in pounds.

UK cost for $5$ litres $= £5.88$

Cost per litre in UK:
$£5.88 \div 5 = £1.176$

2. Convert the UK cost per litre from pounds to Singapore dollars.

Since $£1 = \text{SGD}\char36{}1.70$,

$£1.176 = 1.176 \times 1.70 = \text{SGD}\char36{}1.9992$ per litre

3. Compare the Singapore and UK prices per litre and find the difference.

Singapore cost per litre $= \text{SGD}\char36{}2.98$

Difference:
$2.98 - 1.9992 = 0.9808$

To the nearest cent, $0.9808 \approx 0.98$.