Nelson apparently died some time between April 1930, when he was recorded in the census as age 67, and Oct 1940, when Hannah was recorded as his widow on her death certificate.

Her death certificate records Hannah Sparks, age 79 years 8 months 13 days, born 15 Feb 1861 in Elliott Co., Kentucky, widow of Nelson Sparks, father Jessie Leatingham, mother’s maiden name Sallie Wagner, both born in Kentucky, cause of death bronchial pneumonia, informant Thomas Sparks, Gimlet, Ky, burial in Sparks Cemetery.

Elliott County did not exist in 1861 (it was formed in 1869). In the 1860 census Hannah’s parents were living in Carter Co.

1900 census of Elliott Co., Ky, Sinking precinct, enumerated 6 June, lists on p. 3A as family #39:
Sparks, Nelson, 37, b. Jan 1863, farmer; Hanah, wife, 36, b. Oct 1863, married 14 years, mother of 8 children, 8 living; Clerinda, dau, 13, b. Oct 1886; Eliza, dau, 13, b. Jan 1887; Minta, dau, 11, b. Feb 1889; Mary L., dau, 8, b. Nov 1891; Ellic, son, 7, b. Sep 1892; Jerry, son, 6, b. Aug 1873; James M., son, 3, b. July 1896; Thomas, son, 1, b. Mar 1899; Dianah, mother, 73, b. Mar 1827, widowed, mother of 1 child, 1 living. All born Ky Ky Ky.

Dianah has apparently misinterpreted the question to mean the number of children living with her in the household. She and Thomas had at least 8 children, of whom at least three were still living in 1900, probably more.