Answer:
a) To find 50% of £80, you simply multiply £80 by 0.50 (which represents 50% as a decimal):
\[ \text{50% of £80} = 0.50 \times £80 = £40 \]
b) To find 25% of £80, you multiply £80 by 0.25 (which represents 25% as a decimal):
\[ \text{25% of £80} = 0.25 \times £80 = £20 \]