What are the rules for forming comparatives and superlatives of adjectives ending in -er?

What are the rules for forming comparatives and superlatives of adjectives ending in -er?

The rules for forming comparatives and superlatives of adjectives ending in -er are as follows:

1. For adjectives with one syllable, add -er to form the comparative and -est to form the superlative. For example: tall (comparative: taller, superlative: tallest).

2. For adjectives with two or more syllables, use "more" before the adjective to form the comparative and "most" before the adjective to form the superlative. For example: clever (comparative: more clever, superlative: most clever).

Note: Some adjectives ending in -er may not follow these rules and have irregular comparative and superlative forms.