Media hora, una docena: fractions and amounts

Fractions

Half has two forms. Medio is an adjective meaning half a, and agrees; la mitad is a noun meaning half of:

From a third, the fractions are nouns. A third is un tercio; a quarter to a tenth borrow the ordinals; from an eleventh, Spanish adds -avo:

• Un cuarto de la clase no vino. - A quarter of the class didn't come.

Collective numbers

Spanish has round-number nouns for rough amounts, and each takes de:

• Compré una docena de huevos. - I bought a dozen eggs.
• Había cientos de personas. - There were hundreds of people.

Percentages

Use por ciento with el or un:

• el veinte por ciento - twenty per cent
• un aumento del diez por ciento - a ten per cent rise