The budget proposal released by House Republicans on Tuesday promises it can repeal Obamacare and save the government a lot of money in the process. But the document relies on some vague accounting to justify this claim.

It is easy, of course, to save the federal budget a lot of money by simply eliminating the spending provisions of the Affordable Care Act. Getting rid of the law’s Medicaid expansion to low-income people and its premium subsidies for middle-income insurance shoppers would save about $2 trillion over 10 years, according to the House budget estimates. That number is published clearly and prominently in the budget’s accompanying tables.

Less explicitly accounted for is the fact that the health law, despite its huge federal spending on insurance expansion, was also designed to reduce the deficit. The law imposed substantial cuts to the Medicare program and raised a series of new taxes, including ones on wages, health insurance and medical devices.

Perfect estimates are difficult at this point, because most of those changes are now integrated into current budget estimates, but it’s safe to say that the law’s Medicare cuts save more than $700 billion over the next 10 years, and the taxes will raise around $1 trillion.