When your child logins into their Sumdog child account they will by default be on Math.
If you have a family subscription (or if their school has a subscription for the other subjects) they will be able to select them from their child account.
Subscription subjects will be marked with a gold start to let you know that it is subscribed.
To select another subject your child will need to:
1) Click on the blue subject panel on their City page
2) Select the Subject they would like to work on.
Now when they play the games they will be asked questions on the selected subject.
Note: If they are playing the writing games another member of the family will need to play with them. This is because with the writing games players will be able to have discussions with each other. For security we only allow they to communicate with family members of if they are in school with their class mates. From your parent account you can view your child's discussion and control your child's writing access from here.
If your child does not have a subscription and has tried to select one of the other subjects they will see a similar message.
Here is how you can find out more about how to purchase a family subscription.