Final answer:
If your Grandma did not give you $10 as she said she would, then you do not have to go to school today.
Step-by-step explanation:
In this scenario, if your Grandma says, "If I give you $10, then you have to go to school today," and she did not give you $10, then you can conclude that you do not have to go to school today. This is because the statement your Grandma made was a conditional statement, and in a conditional statement, if the condition is not met, then the conclusion does not follow. Therefore, since your Grandma did not give you $10, the condition was not met, and you do not have to go to school.