1. Expressing Extremes

2. To express extremes with most adjectives, drop the final vowel and add the ending -ísimo(a). The adjective must agree in gender and number with the noun it modifies.
La idea de Rosa es interesantísima.
Rosa’s idea is very (extremely) interesting.

3. When the last consonant is c, the c changes to qu.
rico (a)  riquísimo (a)
When the last consonant is g, the g changes to gu.
largo (a)  larguísimo (a)

4. Changes to following adjectives into superlatives:
Rico
Bueno
Largo
Interesante
Grande
Bello
Caro
Aburrido
Malo
Triste
riquísimo
buenísmo
larguísimo
interesantísimo
grandísmo
bellísimo
carísimo
aburridísimo
malísimo
tristísimo