This is how middah k'neged middah looks written in Hebrew.
Remember Hebrew is read from the right to the left. So the red מ Will be the first letter you read. This is a Hebrew "mem". It is a Hebrew letter with the same sound as the English "M".
I want to show you some Hebrew words: Don't worry if you don't read Hebrew, just look at the similarity of the letters.
This is the Hebrew word for Riches/Wealth = OSHER
Now let's look at a few words related to the word TEN = ESER
Ten = eser (Hebrew)
Tithing = aser (Hebrew)
Tithes = maasar
Now a saying from the Pirkei Avot 3:17
Translation: Tithes are a fence for Riches.
מעשׂרות סיג לעשׁר
The word in Red above is Maasrot (tithes)
The word in Green above is l'osher (riches)
The words for tithe (giving to God) are spelled with the same letters as Riches/Wealth (God giving to us - see 1 Samuel 2:7)