I read this article: 'ABOUT AND BY THE COMMENTATORS: Why do we Eat Matza on Pesach?' written by Rabbi Amnon Bazak, in which he wrote:
Avudraham gives many examples of gematria, the numerical value of the letters of a word or phrase. For example, according to the Talmud, "During prayer, one should keep his feet together, as is written, 'Their feet were straight' [Yechezkel 1:7]" [Berachot 10b]. In the laws of Shemona Essrei, Avudraham writes, "This is symbolized by the fact that 'yeshara' (straight) has the same numerical value as 'tefila' (prayer)." He also adds that the main factors in prayer are avoiding undesired thoughts and maintaining the proper attitude, and he notes that "prayer (tefila) has the same value as 'bekavanat halev' (attitude of the heart) and it is also equal to 'avodat lev' (service of the heart)."
It's the quotation of Avrudraham that really got my interest (Anyone know its source?) But after calculating, i found that tefilah and b'kavanat halev indeed share the same gematria (515), but the gematria of avodat lev is 514; did i miscalculate? or did I not understand the part 'it is also equal to avodat lev' correctly?