Q. Why does my shule add extra shofar sounds at the end of Musaf on Rosh HaShanah?
10 is one of the chief numbers in the Bible, and of course 100 is 10 times ten, so a hundred notes give the impression of completeness. Along similar lines the sages say that a person should say 100 blessings every day.
In relation to the shofar we should bear in mind that it is our call to God and also God’s call to us. We ask God to hear our voice – but at the same time God asks us to hear His voice.
This idea is reinforced by the partnership between the Chumash and the Book of Psalms. The five books of the Chumash are His five-fold call to us; the five sections of T’hillim are our five-fold response.