2) Сократить дроби: 80/75, 100/180, 300/450.

1. \(\dfrac{80}{75}=\dfrac{80:5}{75:5}=\dfrac{16}{15}\).
2. \(\dfrac{100}{180}=\dfrac{100:20}{180:20}=\dfrac{5}{9}\).
3. \(\dfrac{300}{450}=\dfrac{300:150}{450:150}=\dfrac{2}{3}\).

Ответ: \(\dfrac{16}{15};\ \dfrac{5}{9};\ \dfrac{2}{3}\).