You usually start off with twenty baby teeth. If she is losing four each year you would divide the amount of baby teeth by four:
20/4=5
So she lost all her teeth by Five years of age.
PS. which is quite young!
The answer is true hope this helps
7x5 is equal to 35 + the 7 3/4 we have on Saturday = 42 3/4, or it can be rounded to 43
Potential trouble with the law, or social issues like losing your friends.