End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
http://medadsiyah.farafile.ir/file/35291/جزوه-ریاضی-کاربردی--استاد-حسینی-(دانشگاه-اصفهان)