Montana doesn't publish birth dates on-line. You'll have to contact the Daniels County Clerk & Recorder, www.scobeymt.com/government.html
However, I'm sure you'll find they have restrictions about looking up or issuing copies of birth certificates. They won't release death info until 50 years after the person is deceased.
This is what I found about the family.
In 1920 they lived in Taude, Valley, MT.
Albert B. Laurence [how spelled in Census], b. ND, 35, general farmer.
Myrtle, wife, b. MN, 23.
Margaret E., b. MT, 5.
Alton F., b. MT, 3 6/12ths.
Howard M., b. MT, 1 9/12ths.
Vincent L., b. MT, 6/12ths.
In 1930 they were living in Scobey, Daniels, MT.
Albert Laurence, 46, b. ND, general farmer.
Myrtle, b. MN, 33.
Marguerite, b. MT, 15.
Alton, b. MT, 13.
Howard, b. MT, 12.
Vincent, b. MT, 11.
Paul, b. MT, 8.
I didn't find the family in the 1940 Census.