Is That Grandma or the Baby?

This 1850 census entry from Allegany County, Maryland, is split over two census pages. The enumeration for the household headed by John Fletcher indicates the dwelling number is 2620 and the family number is 2658.

1850 U. S. Census, Allegany County, Maryland, district 9, page 375 (upper left), John Fletcher household, dwelling 2620, family 2658 [continued on next page]; digital image at  Ancestry.com. 

The enumerator apparently corrected the dwelling and household numbers for the household members who appear on the subsequent page, writing them over as 2620 and 2658 to indicate they should appear as being in the household headed by John Fletcher and that they were not their own separate household.

I'm not certain about the relationship among the various members of this household. That's not the point of this post--but it is a concern. However, that's not my immediate question.

How old is the Amanda who is listed last in the household? Ancestry.com transcribed the age as 72. I'm thinking that the age is the fractional part of a year with 12 written as the denominator.

For those who understandably need the full image, click on the image below to pull up the full page few of this census record.

Here is  Ancestry.com's database transcription of this entry:

Always look at the image. I'm thinking that's not Grandma. It's the baby.