Riddle of the Week

RIDDLE OF THE WEEK:
My name consists of three letters (first and last remain the same).
If my heart contains 300, I am a prophet and redeemer.
But if I only contains 90, I am a poor man’s bread.
If you will only place a 9, perform wonders and miracles with me.
And if you insert 20, ten were already sent to Egypt.

Answer: A Mem for the first letter and Heh for the last letter.
Insert 300 (letter Shin), then משה
Insert 90 (letter Tzadi), then מצה
Insert 9 (letter Tes), then מטה
Insert 20 (letter Kaf), then מכה