Unstressed Syllables

Find the stressed syllable and spell the quiet one in separate, history, opposite.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 3

In a long word, one syllable gets the most push. That's the stressed syllable. Say separate. The first part, sep, is the strong one.
The other syllables go quiet. Their vowels all sound like a soft uh, which makes them hard to spell. That's why many people misspell separate.
Related words can help, because the stress moves. In define, you hear the i clearly, and that's a clue for definition.
Here's another trick. Say the word in an extra careful way, like sep-a-rate, to remember the spelling.

Georgia's K-12 English Language Arts Standards:

5.F.P.4.a — Decode and encode words with graphemes that represent multiple letter-sound correspondences.
5.F.P.4.b — Decode and encode single-syllable and multisyllabic words of all syllable types.