Rule 29 refers to syllable division. Words are usually divided between double consonants within a base word. When reading we only say one of them. When practising spelling say both consonants so you will spell them correctly.
For example: hap py, sun ny, pup py.
Note: There are more rules explaining syllable division. These are taught in subsequent grammar/spelling lessons.
Watch the tutorial videos below to see how the Spelling Tools, Spelling Rule 29 and Reading Tools are used to spell challenging words.
Special Note:
Not all words will follow the spelling rule. These are called exceptions. If 90% or more words follow this rule then this is still a great tool to help become a proficient speller. Language experience will deal with the rest.