How many Rakat in Salah

For every matured Muslims, five time Salah is mandatory in a day. There are many Rakat in a one time Salah. Rakat details in below
Fajr:
1. First two Rakat are Sunnah 
2. Then two Rakat are mandatory

Duhr:
1. First four Rakat are Sunnah
2. Then four Rakat are mandatory
3. Then two Rakat are Sunnah
4. Then two Rakat are nafl (optional) 

Asr:
1. First four Rakat are Sunnah (optional)
2. Then fore Rakat are mendatory

Maghrib:
1. First three Rakat are mandatory
2. Then two Rakat are Sunnah
3. Then two Rakat are nafl (optional)

Isha:
1. First four Rakat are Sunnah (optional)
2. Then four Rakat are mandatory
3. Then two Rakat are Sunnah
4. Then two Rakat are nafl (optional)
5. Then tree Rakat are Wajib ( mandatory) 
Total 20 Rakat are mandatory and the rest Sunnah & nafl