Front 8 teeth that is upper central and lateral incisors and lower central and lateral incisors shed between 6-8 years of age.
So the number of teeth that are falling are in time. You may expect one more tooth falling within next six month.
No need to worry until new teeth are erupting on time.
Next Steps
Wait for 3-4 months after a milk tooth has fallen. If you do not see a permanent tooth erupting in its place even after 4 months consult your dentist and if required get x- ray done.
Health Tips
Give your child food like coconut, corn. The effort put in chewing these foods tends to encourage tooth eruption(growth)