If my wife baby sits 10 and a half hours 5 days, sometimes 6 a week, are the two grandkids dependants?

[VolvoGirl]

Does she get paid for watching them?

[SweetieJean]

Is she paid to do this?

[we3laphams]

No, she doesn't get paid.

[SweetieJean]

As indicated below, they are not your dependents.
Ask their parents about paying you going forward.

[Leonard]

No, they do not meet all the test to be considered as your dependants

You can claim them if you provide more than half their total support. Here are all the requirements:

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.

2. The person either (a) must be related to you or (b) must live with you all year as a member of your household. 

3. The person's gross taxable income for the year must be less than $4,150 in 2018. Social Security income is not included in this limit. 

4. You must provide more than half of the person's total support for the year.

5. The person must be a U.S. citizen, U.S. resident alien, U.S. national, or a resident of Canada or Mexico.