vs
QUICK ANSWER
"Si" is a form of "si", a conjunction which is often translated as "if". "Creo" is a form of "creo", a phrase which is often translated as "I believe". Learn more about the difference between "si" and "creo" below.
si(
see
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
creo
A phrase is a group of words commonly used together (e.g., once upon a time).
a. I believe
Creo que todos tienen que ayudar a cuidar el planeta.I believe everybody has to help save our planet.
2. (I suppose)
a. I think
¿Cuál es el apartamento de Alicia? - Creo que vive en el cuarto piso.What's Alicia's apartment? - I think she lives on the fourth floor.
