Even though English is inconsistency in terms of spellings of a word and pronunciation of the word, there are few rules which helps in understanding the spelling patterns of few common words.
This rhyme is one such rule. It helps in picking the digraph ie or ei for a category of words that were basically borrowed from French like receive, receipt etc.
According to tis rule if you are unsure whether a word is spelled with the digraphei or ie, the rhyme suggests that the correct order is ie unless the preceding letter is c, in which case it may be ei.
Friend , Theif, Piece- these words have digraph ie in them.
Receive , Deceive – these words have ei due to letter c preceding the digraph.
Hoeever there are exceptions to this rule
ieafter c: species, science, sufficie
einot preceded by c: seize, vein, weird.
Here is the anchor chart and worksheet to practice this rule. All these anchor charts and worksheet are free for download for classroom use or to use them at home but do not use them commercially.