Before reading the model, ask a helper to say chief and hide all printed copies. Write it from memory and compare c-h-i-e-f. Keep ie in that order. In a sentence, chief can name a leader or describe the main thing. For the plural chiefs, keep f and add s.
Worked example
Our chief goal is to help. Here chief describes the main goal. Two fire chiefs met. Chiefs names more than one leader.
A fresh writing try
Write the word from memory with the page covered. Then uncover it and check every letter. Write a new sentence about a fictional leader or a main goal. Explain your meaning to a helper. These written attempts are separate from the checked choices below.