i don't think so
With 45k salary she takes home around 30k. However, she has benefits like paid sick days and vacation days. Also she has retirement saving, which belongs totally to her. As a public school teacher, I wonder she also has a pension.
After 12k day care cost, she earn 18k profit. However, she forgets to mention 5k tax benefit of her day care cost.
Not bad at all, compared to $0 to stay at home.
